DOI: 10.3897/compcytogen.20.213474

Authors: Robert B. Angus

Abstract: Triploid female Helophorus brevipalpis Bedel, 1881 are recorded from one locality near Oslo, Norway. Analysis of their karyotypes using both conventional Giemsa staining and C-banding reveals a chromosomal arrangement similar to that shown by English diploid material and different from the arrangements shown by known parthenogenetic populations in Spain, France and Italy, indicating that this parthenogenesis has evolved independently.

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DOI: 10.3897/compcytogen.20.205237

Authors: Derya Güloğlu

Abstract: Medicago sativa Linnaeus, 1753 (Leguminosae) is a globally important autotetraploid forage crop with a complex genome. Local populations adapted to specific ecological niches, such as those in Türkiye’s Lake Region, represent valuable genetic resources for breeding. However, their cytogenetic diversity remains poorly characterized. This study aimed to perform detailed karyotype analyses of eight alfalfa populations from this region to assess chromosome number, morphology, asymmetry, and structural variants. Root tips from eight populations collected from Afyonkarahisar, Burdur, Isparta, and Konya provinces were analyzed using aceto-iron-hematoxylin staining and the squash technique. Chromosome measurements, arm ratios, centromeric indices, karyotype formulas, and asymmetry indices (intrachromosomal A1 and interchromosomal A2) were determined. Descriptive parameters (TF%, DRL, DI) and clustering analyses were used to compare cytogenetic diversity among populations. In accordance with current karyomorphological recommendations, mean centromeric asymmetry (MCA), coefficient of variation of chromosome length (CVCL), and coefficient of variation of centromeric index (CVCI) were additionally reconstructed from the chromosome-pair mean measurements reported in the paper. All populations were confirmed as autotetraploid (2n = 4x = 32). Karyotypes consisted predominantly of metacentric chromosomes, with fewer submetacentrics, and all possessed four satellite chromosomes. Reconstructed MCA ranged from 11.86% (Bolvadin-3) to 15.36% (Yalvaç-3), CVCL ranged from 8.81% (Akşehir-2) to 12.69% (Bolvadin-3), and CVCI ranged from 7.77% (Bucak-2) to 11.63% (Yalvaç-3). A1 ranged from 0.208 (Bolvadin-3) to 0.258 (Hüyük-2), and A2 ranged from 0.096 (Yeşilova-3) to 0.149 (Hüyük-2). B-chromosomes (2n = 32 + 2B) were detected exclusively in Bucak-2, and heteromorphic chromosome pairs were observed in Hüyük-2 and Uluborlu-1. Hüyük-2 remained the most structurally distinctive population because of its high A1 and A2 values, heteromorphic chromosome pair, enlarged satellite, and Stebbins 2C classification. Cluster analysis based on asymmetry indices separated Hüyük-2 as a distinct, highly asymmetric group. Substantial cytogenetic diversity exists among Turkish Lake Region alfalfa populations, including rare features such as B-chromosomes and heteromorphic pairs. These findings highlight the value of local germplasm as genetic resources for conservation and breeding. The Hüyük-2 population, with its highly asymmetric karyotype, is particularly noteworthy for further evolutionary and applied studies.

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DOI: 10.3897/compcytogen.20.191955

Authors: Jiayu Jin, Jing Dai, Jianping Ye

Abstract: The small-sized Crocidura horsfieldii (Tomes, 1856) species complex, comprising C. watasei (Kuroda, 1924), C. tadae (Tokuda et Kano, 1936), C. kurodai (Jameson et Jones, 1977), C. wuchihensis (Wang, 1966), and C. indochinensis (Robinson et Kloss, 1922), has long been the subject of taxonomic confusion in the literature. Here, we report for the first time the karyotype of female C. indochinensis from Yongde Snow Mountain, based on conventional Giemsa staining and the GTG-banding technique. C. indochinensis has 2n = 38 and FN = 56. The autosomes consist of four metacentric or submetacentric pairs, four subtelocentric pairs, and ten acrocentric pairs, whereas the X chromosome is a medium-sized submetacentric. Our results demonstrate that the karyotype of C. indochinensis differs markedly in 2n and FN from those of C. horsfieldii, C. watasei, C. tadae and C. kurodai, providing further evidence for the distinct species status of C. indochinensis within this complex. Furthermore, comparative analysis of the G-banded chromosomes of C. indochinensis and C. dsinezumi revealed a high degree of karyotypic homology, with their karyotypes differing primarily by a single fusion/fission event and a centromeric shift or a pericentric inversion, thereby enhancing our understanding of karyotype evolution within the genus Crocidura Wagler, 1832.

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DOI: 10.3897/compcytogen.20.206266

Authors: Paulo Augusto de Lima-Filho, Gideão Wagner Werneck Félix da Costa, Simião Alefe Soares da Silva, Wagner Franco Molina

Abstract: Gobies (family Gobiidae) rank among the most diverse of all marine fish families. Although the cytogenetics of these small, ubiquitous fish is still a young field, studies on Atlantic species, despite their limited number, have already revealed a remarkable level of karyotypic variation. This karyotype diversity has provided critical evidence for discovering new species, uncovering population structures, identifying sex chromosomes, and pinpointing major shifts in repetitive DNA. This study presents the first chromosomal characterization of two Atlantic goby species, Coryphopterus glaucofraenum (Gill, 1863) and Evorthodus lyricus (Girard, 1858), using classical cytogenetics and base-specific fluorochrome staining. Our analyses revealed a striking divergence in their karyotypes. Evorthodus lyricus exhibited a karyotype of 2n = 46 (FN = 92), whereas C. glaucofraenum presented 2n = 40 (FN = 42), indicating significant differences in both chromosome and fundamental number (FN). These cytogenetic patterns, combined with existing data for the family, reinforce the high karyotypic diversity within Gobiidae and suggest a relationship between speciation processes and chromosomal modifications in the diversification of this family.

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DOI: 10.3897/compcytogen.20.198500

Authors: Desislava Stoianova, Gayane Karagyan, Snejana Grozeva

Abstract: Telomeric sequences in the insect infraorder Nepomorpha (Hemiptera: Heteroptera) have previously been characterized only in the basal superfamily Nepoidea, where the canonical arthropod motif (TTAGG)n was confirmed by fluorescence in situ hybridization (FISH). The telomeric repeat composition of the remaining Nepomorpha superfamilies remained unknown. Using TREW, a tool for de novo identification of candidate telomeric sequences from short-read whole-genome sequencing data, we screened 32 publicly available NCBI datasets representing 24 genera and all 13 Nepomorpha families. The method was validated against species with known (TTAGG)n telomeres in Nepoidea, successfully recovering the expected motif. In Corixoidea, (TTAGG)n was uniformly identified as the best candidate for telomeric sequence across all eight species of three families – Corixidae, Diaprepocoridae and Micronectidae. In contrast, derived 10-bp motifs were recovered from the remaining four superfamilies: (TGGTTAGTGA)n and (TGGTTAGTGT)n in Ochteroidea, (TGGATAGGTG)n and (TGGATAGGAG)n in Naucoroidea (including Aphelocheiridae and Potamocoridae), and (TGGATAGGGT)n uniformly across Notonectoidea and Pleoidea. All derived decamers except those from Ochteroidea share the core octamer TGGATAGG. The retention of (TTAGG)n in the two basal superfamilies and the occurrence of derived decamers in more derived clades are congruent with most current phylogenetic hypotheses for Nepomorpha and support independent evolution of 10-bp motifs within the infraorder. The presence of an identical candidate for telomeric sequence – (TGGATAGGGT)n in Notonectoidea and Pleoidea provides additional support for their close phylogenetic relationship and might be a synapomorphy for this clade. These findings extend the known pattern of telomeric diversification within Heteroptera to Nepomorpha and demonstrate the utility of short-read archival data for taxonomic surveys of telomeric composition.

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DOI: 10.3897/compcytogen.20.190408

Authors: Yuliya N. Smotrova, Mikhail Gr. Monakhos, Olga V. Razumova, Dmytry V. Romanov

Abstract: Cytogenetic analysis of Citrus Linnaeus, 1753 species is complicated by the small size and morphological similarity of their chromosomes. In this study, we applied the fluorescence in situ hybridization (FISH) method using rDNA probes, as well as newly developed oligonucleotide probes based on previously uncharacterized tandem repeats identified in citrus genomes. Four tandem repeats (CL1, CL14, CL262, and CL122) were mapped to the chromosomes of five Citrus species: Citrus medica Linnaeus, 1753, Citrus × aurantiifolia (Christmann, 1777) Swingle, 1913, Citrus × limon (Linnaeus, 1753) Osbeck, 1765, Citrus myrtifolia Rafinesque, 1838, and Citrus × latifolia Tanaka, 1951. The repeats exhibited distinct and partially species-specific distribution patterns: CL1 was detected in all species, whereas CL262, CL122, and CL14 exhibited more restricted localization. A comparative analysis of their chromosomal distribution in relation to 45S- and 5S-rDNA loci revealed differences between the conserved regions of ribosomal DNA and the more dynamic tandem repeats. The identified repeats represent useful cytogenetic markers for chromosome identification, karyotyping, and comparative analysis within the genus Citrus.

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DOI: 10.3897/compcytogen.20.190559

Authors: Gideão Wagner Werneck Felix da Costa, Oscar Akio Shibatta, Marcelo de Bello Cioffi, Jhon Alex Dziechciarz Vidal, Luiz Antonio Carlos Bertollo, Wagner Franco Molina

Abstract: Flying fishes (Exocoetidae) constitute a group of fish with adaptations for life in the epipelagic zone, notably featuring one or two pairs of expanded fins that enable gliding flight. Most of their 80 species have an interoceanic distribution, where they stand out as economic resources, as well as a key component of the trophic base of large pelagic predators. However, despite being a charismatic evolutionary model with considerable knowledge about its biology, that group remains neglected regarding its cytogenetic characterization. Here, we performed cytogenetic analyses for the first time in Hirundichthys affinis (Günther, 1866) (two Atlantic populations) and in Cheilopogon exsiliens (Linnaeus, 1771) and C. furcatus (Mitchill, 1815) (Saint Peter and Saint Paul Archipelago, mid-Atlantic region). These analyses included C-banding, silver nitrate staining (Ag-NOR), and fluorescent in situ hybridization (FISH) with 18S rDNA, 5S rDNA, and (CA)15 microsatellite probes. The three species share 2n = 48 but exhibit discernible intergeneric karyotypic divergences. Thus, while the karyotype of H. affinis displays exclusively acrocentric chromosomes (48a, FN = 48), C. exsiliens (2st+46a, FN = 50) and C. furcatus (2m+46a, FN = 50) both differ due to one pair of bi-armed chromosomes. Heterochromatin shows an occasional accumulation of (CA)15 clusters predominantly in pericentromeric regions of the chromosomes. The rDNA sites display variations in number and location, proving to be effective cytotaxonomic and population markers for the group. Our data indicate that the distribution of the flying fishes was accompanied by their chromosomal reorganizations. Thus, cytogenetic data stand out as promising tools for unraveling environmental adaptations, reproductive isolation, and speciation in the vast epipelagic areas they occupy.

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DOI: 10.3897/compcytogen.20.184176

Authors: Lin Fu, Ziyue Liu, Lina Han, Ting Zhang, Yan Jiang, Denis A. Krivenko, Jin Hu, Hongfeng Chen, Lei Duan

Abstract: Polygala fallax Hemsley, 1886 is a perennial herb of the family Polygalaceae. Because of its antioxidant, anti-aging, anti-inflammatory, and antibacterial properties, it is regarded as a traditional medicinal plant in China with high economic value. Although this species has significant medicinal and health benefits, cytological research on it remains very limited. In the present study, the genome size and chromosome number of P. fallax were determined through k-mer analysis, flow cytometry, and cytogenetics. Firstly, a genome survey was conducted using Illumina NovaSeq 6000 DNA sequencing. K-mer analysis revealed that the genome size of P. fallax was approximately 2199.64 Mb (ca. 2.20 Gb), the heterozygosity rate was about 1.11%, and the proportion of repeated sequences was about 73.61%. As for flow cytometry analysis, Solanum lycopersicum Linnaeus, 1753 was used as internal standard species, and the 2C-DNA value of P. fallax is 2.49 Gb. We counted the chromosome number of P. fallax using a common cytogenetic method, and the result showed a chromosome number of 2n = 40. This comprehensive study offers a foundation for subsequent whole-genome sequencing of P. fallax, contributing valuable insights into its genetic characteristics and providing genomic information for further research on the synthesis mechanisms of its medicinal secondary metabolites, species conservation, and sustainable utilization.

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DOI: 10.3897/compcytogen.20.185104

Authors: Gökhan Yürümez

Abstract: In this study, five blind mole rat specimens of the Nannospalax sp. were collected from two different localities in Muş Province, Eastern Anatolia, Türkiye. Cytogenetic analyses of these specimens revealed that the diploid chromosome number, the fundamental chromosome number, and the number of autosomal arms were 2n = 52, NF = 84 and NFa = 80, respectively. The X chromosome was medium-sized and submetacentric, while the Y chromosome was small and acrocentric. Active nucleolus organizer regions (NORs) were observed on the telomeric regions of three bi-armed autosomal pairs in all examined specimens. This study presents new karyological data regarding the blind mole rat with 2n = 52 chromosomes distributed in the Eastern Anatolia region from Türkiye.

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DOI: 10.3897/compcytogen.20.175870

Authors: Rodrigo Batista Lod, Luísa Antônia Campos Barros, Linda Inês Silveira, Esthefanne de Araújo Leitão, Gisele Amaro Teixeira, Hilton Jeferson Alves Cardoso de Aguiar

Abstract: Ants are present in different environments and regions of the planet, showing little-known biodiversity in the Neotropics, especially among fungus-growing ants (the subtribe Attina). Recent studies seek to combine morphological analysis with other methods, such as cytogenetics, to better define and differentiate species. In this sense, cytogenetic analyses have been important for the study of ants, characterizing chromosome number and morphology, and mapping rDNA genes and microsatellites, which generate important information about the evolution and taxonomy in Attina species. In the Amazon region, there are still few studies that include cytogenetics in their research. In this study, we cytogenetically characterized five fungus-growing ants, belonging to the genera Cyphomyrmex Mayr, 1862 and Apterostigma Mayr, 1865, from the northernmost region of Amapá state within the Guiana Shield region of Brazil. The nests were captured by active search, and the larvae had their brain ganglia extracted to provide metaphase chromosomes. The karyotypes were determined using Giemsa or DAPI staining, and 18S ribosomal DNA (rDNA) and (GA)n microsatellite repetitive sequences were physically mapped with FISH technique with specific probes. Cyphomyrmex transversus Emery, 1894 had 2n = 24 chromosomes (18m+6sm) and Cyphomyrmex laevigatus Weber, 1938 n = 7, all metacentrics. In both species, the rDNA clusters were restricted to a single chromosome pair. In C. transversus the rDNA clusters were mapped to the long arm of the larger submetacentric chromosome pair, while in C. laevigatus they were on the short arm of the fifth chromosome (haploid individuals). These data are aligned to Cyphomyrmex species previously studied from this region. Although the FISH protocol was successfully applied to Cyphomyrmex species, it was unable to localize rDNA sites in the chromosomes of all three Apterostigma species, suggesting that methodological adjustments are required for an effective application to this genus. In Apterostigma, the largest chromosome number of the genus was identified in Apterostigma tropicoxa Lattke, 1997, with 2n = 54 chromosomes, while A. jubatum Wheeler, 1925 and A. andense Lattke, 1997 had 2n = 22 and n = 11 respectively but were strikingly diverse in their karyotype configurations. In C. laevigatus and C. transversus the microsatellite (GA)n clusters were scattered on all chromosomes. While A. jubatum also had a scattered distribution pattern of this microsatellite on all chromosomes, the other Apterostigma species showed more complex patterns. In A. andense these microsatellite sequences were more concentrated at the ends of some chromosomes, while in Apterostigma tropicoxa they were almost absent in the short arms of several submetacentric and subtelocentric chromosomes. The cytogenetic data for Amazonian species in this study highlight the chromosomal diversity among fungus-growing ants, particularly within the genus Apterostigma, providing useful insights into the karyotype evolution of these ants and paving the way for further cytogenetic research in the Amazon region.

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DOI: 10.3897/compcytogen.20.180400

Authors: Vladimir E. Gokhman, Feliciana Pica, Fortuna Miele, Francesco Nugnes

Abstract: The parasitoid wasp Aganaspis daci (Weld, 1951) is a natural enemy of several tephritid fruit flies and was recently detected for the first time in Italy. Despite its biological and applied relevance, no chromosomal data have been available for this species until now. Here we provide the first karyotype description of A. daci, based on specimens from a laboratory stock in Campania (Italy), using chromosome morphometry and acridine orange staining. This species has n = 9 and 2n = 18, with a very large first metacentric chromosome, and acrocentrics prevailing among the remaining ones. The sixth metacentric presumably carries a single nucleolus organizing region (NOR). Staining with acridine orange provides homogeneous staining of all chromosomes. A brief review of the chromosome study of parasitoids of the family Figitidae, which have n = 5 to 11, is given. The haploid karyotype of ten chromosomes apparently represents the ancestral character state at least for the subfamily Eucoilinae, with chromosome sets that include n = 9 and the very large first metacentric, likely result from independent chromosomal fusions.

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DOI: 10.3897/compcytogen.20.177662

Authors: Sergey Matveevsky, Oxana Kolomiets, Tatiana Grishaeva, Aleksey Bogdanov, Valentina Tambovtseva, Irina Bakloushinskaya

Abstract: We first studied several rare cases of over-diploid spermatocyte emergence using advanced immunocytochemical methods and a cross-species approach in subterranean rodents Ellobius tancrei (Blasius, 1884), E. alaicus Vorontsov et al., 1969, E. talpinus (Pallas, 1770), and Nannospalax leucodon (Nordmann, 1840) (all belong to the order Rodentia). The tetraploid spermatocytes exhibited specific features during meiotic prophase I, including symmetric and asymmetric chromosome quadrivalents with partner-switching, extended asynapsis, altered recombination patterns, and variable chromatin inactivation. These anomalies suggest that meiotic checkpoints, which are potentially triggered by failed synapsis or incomplete sex chromosome silencing, may act to prevent progression of polyploid spermatocytes. However, the quadrivalents assembled shelterin complexes at chromosome ends, as observed in E. talpinus, and these ends were connected to the nuclear envelope through the linker of nucleoskeleton and cytoskeleton (LINC) complex, as observed in E. alaicus, similarly to normal spermatocytes.

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DOI: 10.3897/compcytogen.20.182675

Authors: Natalia V. Golub, Vladimir A. Lukhtanov, Natalia S. Khabazova, Boris A. Anokhin, Nazar A. Shapoval, Galina N. Shapoval, Ilya A. Gavrilov-Zimin

Abstract: The article is dedicated to the anniversary of Professor, Dr. Sci. Valentina G. Kuznetsova, Editor-in-Chief and co-founder of the journal “Comparative Cytogenetics”. V. Kuznetsova is the principal researcher at the Zoological Institute of the Russian Academy of Sciences, Head of the Department of Karyosystematics. Under her leadership, many Russian and foreign cytogeneticists have successfully defended their dissertations. Today, Valentina Kuznetsova is one of the world’s leading experts in the field of comparative cytogenetics and karyosystematics of insects. The list of her publications includes 200 scientific articles, chapters in books and collective monographs.

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DOI: 10.3897/compcytogen.20.170539

Authors: Lucas S. F. Rachid, Yatiyo Yonenaga-Yassuda, Miguel Trefaut Rodrigues, Katia Cristina Machado Pellegrino

Abstract: Gymnophthalmidae is a monophyletic family of currently 297 Neotropical lizard species. Over the past 25 years, molecular studies have redefined previous morphology-based classifications, confirming the family’s monophyly and revealing three major clades plus Rachisaurinae: ((Riolaminae(Rachisaurinae(Gymnophthalminae)))(Cercosaurinae)). Despite increased taxonomic efforts, especially in the tribes Bachiini and Cercosaurini, of Cercosaurinae, cytogenetic data remain limited. Of over 200 species in these tribes, only three had published karyotypes. Here, we provide new karyotypic data for seven species of Cercosaurini using standard cytogenetic techniques (Ag-NOR, C- and RBG-banding). Diploid numbers ranged from 2n = 32 in Bachia dorbignyi (Duméril et Bibron, 1839) to 2n = 58 in Placosoma glabellum (Peters, 1870). Almost all species displayed karyotypes composed of macro- and microchromosomes, that varied in morphology. Ag-NORs were observed on macro- or microchromosomes in several species, with notable variability in Bachia bresslaui (Amaral, 1935). Constitutive heterochromatin was mostly restricted to centromeric or telomeric regions. In Bachia dorbignyi, we found a putative XX:XY system due to the presence of a dot-like microchromosome exclusively in male specimens. These results comprise the threefold amount of cytogenetic data available for Bachiini and Cercosaurini and help fill a major gap into our understanding of diversity and chromosome evolution within Gymnophthalmidae.

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DOI: 10.3897/compcytogen.20.162616

Authors: Danon Clemes Cardoso, Maykon Passos Cristiano

Abstract: Ribosomal DNA (rDNA) clusters are important cytogenetic markers that can inform both taxonomic delimitation and chromosomal evolution in ants. In this study, we molecularly characterize and validate the widely used 18S rDNA probe applied in cytogenetic studies of Hymenoptera and provide new FISH-based chromosomal data for two previously unstudied leaf-cutting ant species (Acromyrmex ambiguus (Emery, 1888) and Ac. crassispinus (Forel, 1909)). While the general distribution of 45S rDNA loci in leafcutting is relatively well documented (copy number and site), we expand the comparative framework by testing the phylogenetic structure of rDNA positioning across genera. Our results confirm the conserved number of rDNA loci per species but reveal lineage-specific variation in chromosomal location, including both subterminal and pericentromeric arrangements. Phylogenetic signal analyses suggest non-random patterns consistent with evolutionary constraints in locus positioning. Together, our findings refine current cytogenetic models for leafcutting ants and demonstrate the utility of rDNA as a cytotaxonomic character and evolutionary marker for assessing chromosomal diversification.

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DOI: 10.3897/compcytogen.19.172398

Authors: Veronika V. Golygina

Abstract: Data on chromosomal polymorphism in two natural populations from the Inya River in Western Siberia (Novosibirsk province) of Chironomus sp. J (Kiknadze, 1991) —one of the sibling species from the Chironomus plumosus group — are presented for the first time. The species belongs to the “thummi” cytocomplex with 2n = 8 and the arm’s combination AB CD EF G and is closely related to Ch. nudiventris Ryser, Scholl et Wülker, 1983, which has 2n = 6 with the arm’s combination AB CD GEF (a modified “thummi” cytocomplex). The main difference between these two species is the number of chromosomes, apart from that they only differ by the frequencies of banding sequences in arm A, and the presence or absence of some polymorphic inversions. The banding sequence pool of Chironomus sp. J consists of 15 banding sequences. Inversions were found in five chromosomal arms – A, B, D, E, F. The most polymorphic arms were B and D. Two studied populations differed by the level of chromosomal polymorphism with one population being completely monomorphic and the other showing high level of polymorphism with 62–65% of heterozygotes and 0.83–0.88 heterozygotic inversion per larva (depending on the year of collection). Comparison of banding sequences to other species from the group showed that Chironomus sp. J is indeed closest to Ch. nudiventris, with the cytogenetic distance of 0.058 or 0.471 depending on the method of calculation, which indicates that these two species are very closely related. The relationship between Chironomus sp. J and other species from the Ch. plumosus group was discussed.

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DOI: 10.3897/compcytogen.19.165160

Authors: Juliana F. de Lima, Marielle C. Schneider, Leonardo S. Carvalho, Ricardo Pinto-da-Rocha

Abstract: Bothriurus Peters, 1861 is one of the most diverse genera within the family Bothriuridae. However, to date, only five species have been analyzed using a cytogenetic approach. In this study, for the first time, two populations of Bothriurus asper Pocock, 1893 and nine populations of Bothriurus rochai Mello-Leitão, 1932, two species from northeastern Brazil, were analyzed with respect to diploid number, chromosomal behavior during meiosis, and the localization of heterochromatin and nucleolus organizer regions (NORs). For B. asper, a diploid number of 2n = 30 was recorded in geographically distant populations, whereas B. rochai exhibited intraspecific variation in diploid number (2n = 16 and 2n = 18), representing the lowest diploid numbers ever reported for the family Bothriuridae. Despite the variability in diploid number, the number and localization of NORs remained stable among the populations of B. rochai. When comparing heterochromatin patterns between the two species, larger blocks of constitutive heterochromatin were observed in B. asper than in B. rochai. Variation in the amount of heterochromatin among populations of B. rochai was also observed; in this case, the population with the lowest amount of heterochromatin also exhibited the greatest variation in post-pachytene cell configurations. This is the first study to cytogenetically analyze multiple populations of species within the genus Bothriurus, and it significantly expands the karyotypic information available for scorpions with monocentric chromosomes.

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DOI: 10.3897/compcytogen.19.171637

Authors: Pedro Henrique Pacheco Mosquini, Lucas Henrique Bonfim Souza, Juan Martín Ferro, Luciana Bolsoni Lourenço

Abstract: The anuran species group Physalaemus gracilis comprises six species, and variation in the location of nucleolus organizer regions (NORs) was observed across the four species that have been karyotyped to date. The NORs are located interstitially on chromosome 8 of P. carrizorum Cardozo et Pereyra, 2018, and P. lisei Braun et Braun, 1977, terminally on chromosome 8 of P. gracilis (Boulenger, 1883), and terminally on chromosome 10 of P. barrioi Bokermann, 1967. To contribute to the comparative analysis of this group, including the assessment of the hypothesis of homology among these NOR-bearing chromosomes, we described the karyotype of P. evangelistai Bokermann, 1967, and expanded the cytogenetic analyses of P. carrizorum, P. lisei, and P. barrioi. We used classical cytogenetic techniques and mapped, by fluorescent in situ hybridization (FISH), two repetitive sequences: the PcP190 satellite DNA and the U2 snRNA gene. Physalaemus evangelistai exhibited a 2n = 22 karyotype, with meta- and submetacentric chromosomes, which corresponds to the typical karyotypic configuration of the genus. We found an interstitial heterochromatin DAPI-positive band on the short arm of the NOR-bearing chromosomes 8 of P. evangelistai and P. carrizorum from Palmas-PR, and chromosome 10 of P. barrioi, which corroborates the hypothesis that these chromosomes are homologous. In P. evangelistai, an additional NOR was observed on chromosome 9 of females. Moreover, the karyotype of P. carrizorum from Palmas-PR differed from that previously described for P. carrizorum from Misiones, particularly in the number of PcP190 clusters and intrachromosomal position of the NOR on chromosome 8. Specimens from Palmas-PR showed a terminal NOR on chromosome 8 and PcP190 clusters on chromosomes 1 and 3, whereas those from Misiones had an interstitial/pericentromeric NOR on chromosome 8 and a single PcP190 cluster on chromosome 3. Further analyses are still needed to assess whether these cytogenetic differences represent interspecific variation.

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DOI: 10.3897/compcytogen.19.169353

Authors: Robert B. Angus, Fenglong Jia

Abstract: Checking old unphotographed slides of chromosome preparations in the possession of R.B.A. revealed one slide labelled “frater ♀7g 6/6/13 ✓”. The beetle with these data is a female paratype of H. aquila Angus et al., in the general collection of the Natural History Museum, London. One almost complete dividing nucleus was found, with 32 chromosomes, indicating a triploid nucleus with one chromosome lost in the course of preparation of the slide.

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DOI: 10.3897/compcytogen.19.158987

Authors: Koji Iizuka, Hiroyuki Koishi, Nikolay A. Poyarkov, Yoshinori Takeuchi, Yu-Ten Ju

Abstract: The chromosome number of Hynobius fucus was found by Lai and Lue (2008) to be 2n = 58, displaying a karyomorph similar to those previously reported in stream-type salamanders from Taiwan. Based not only on cytogenetic features but also on developmental characteristics such as the embryonic stage and the presence of interdigital membranes during limb formation this species can be confidently classified as a lotic stream-type salamander. Morescalchi (1975) proposed that karyotype evolution in families of urodeles tends to proceed from higher to lower chromosome numbers. Our findings from Taiwan suggest karyotype evolution within the genus Hynobius, that is, the chromosome number of this species may have increased from 2n = 56 in the pond-type ancestor to 2n = 58 in this stream-type lineage.

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DOI: 10.3897/compcytogen.19.157310

Authors: Analyn B. Baldove, Masumi Ito, Takahiro Taguchi, Takuma Mezaki, Hiroumi Saito, Sam Edward Manalili, Yuji Namura, Ivy Jamela Nieves-Brutas, Akira Tominaga, Satoshi Kubota

Abstract: Scleractinian (stony) corals are foundational to reef ecosystems, yet their taxonomy remains unresolved due to morphological plasticity and limited cytogenetic data. This study presents the first molecular cytogenetic characterization of the scleractinian coral Micromussa amakusensis (Veron, 1990), employing fluorescence in situ hybridization (FISH) to isolate and map five DNA markers. Using the conventional Giemsa staining technique, M. amakusensis was found to have a diploid karyotype of 2n = 28, with a prominent homogeneously staining region (HSR) on the long arm of chromosome 12. Subsequently, five FISH markers designated as MA-H3 for histone H3, MA-5S for 5S rRNA, MA-18/28S for 18S-28S rRNA, MA-13C for centromeric region, and MA-TEL for telomeric region were cloned, sequenced, and mapped using FISH. FISH analysis revealed that the MA-H3 localized to the centromeric region of chromosome 1, MA-5S to the telomeric region of chromosome 4, MA-18/28S to the terminal region of chromosome 12 (coinciding with the HSR), MA-13C to the centromere of chromosome 13, and MA-TEL to multiple telomeric regions across several chromosomes. Sequence analysis confirmed marker identities and revealed conserved and novel repetitive elements. Furthermore, Genomic DNA hybridization (GDH) of whole-sperm DNA revealed signals collected at several telomeric regions, suggesting the presence of repetitive sequences. These cytogenetic markers enable the identification of at least 3 out of 14 chromosome pairs, allow for more precise karyotyping, and highlight chromosomal features that may help resolve coral classification and improve understanding of genome evolution. This research demonstrates the utility of molecular cytogenetics in stony coral systematics and provides new FISH markers for future comparative genomic studies.

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DOI: 10.3897/compcytogen.19.164044

Authors: Biplab Kumar Bhowmick, Sumita Jha

Abstract: The cytogenetic relationships in the species of Cucurbitaceae are becoming immensely important to answer questions pertaining to genome evolution. Here, a simplified and updated data resource on cytogenetics of Cucurbitaceae is presented on the basis of foundational parameters (basic, zygotic and gametic chromosome numbers, ploidy, genome size, karyotype) and molecular cytogenetics. We have revised and collated our own findings on seven agriculturally important Indian cucurbit species in a comparative account with the globally published reports. Chromosome count (of around 19% species) shows nearly three-fold differences while genome size (of nearly 5% species) shows 5.84-fold differences across the species. There is no significant correlation between chromosome numbers and nuclear genome sizes. The possible trend of evolution is discussed here based on molecular cytogenetics data, especially the types and distribution of nucleolus organizer regions (NORs). The review supersedes the scopes of general chromosome databases and invites scopes for continuous updates. The offline resource serves as an exclusive toolkit for research and breeding communities across the globe and also opens scope for future establishment of web-database on Cucurbitaceae cytogenetics

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DOI: 10.3897/compcytogen.19.162685

Authors: Robert B. Angus

Abstract: Triploid female Helophorus brevipalpis Bedel, 1881 are recorded from two localities in Provence, France. Their karyotypes are analysed using both chromosome morphology and C-banding. Their karyotypes appear to be identical with those of Spanish material recorded by Angus (1992) but show minor differences from Italian triploid material described by Angus, Jia (2020). Data on C-banding in English H. brevipalpis are given and chromosomal variation in H. brevipalpis is discussed.

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DOI: 10.3897/compcytogen.19.156983

Authors: Natalia Golub, Boris Anokhin, Valentina Kuznetsova

Abstract: We report on the results of a chromosomal study of the big-eyed true bug Geocoris dispar Waga, 1839 (Heteroptera: Geocoridae) aimed at obtaining data on its telomeres. Using fluorescence in situ hybridization (FISH), we have shown, that G. dispar has a non-canonical 10-bp telomeric motif TTAGGGGTGG. This is the first evidence of telomere structure in the family Geocoridae and the first finding of the telomeric sequence (TTAGGGGTGG)n in the large superfamily Lygaeoidea (infraorder Pentatomomorpha).

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DOI: 10.3897/compcytogen.19.151345

Authors: Sergey A. Simanovsky, Alexandra Yu. Skuratovskaya, Margarita G. Simonian, Dmitry A. Medvedev, Fekadu Tefera, Alexander S. Golubtsov

Abstract: The African non-annual killifish genus Epiplatys Gill, 1862 (family Nothobranchiidae) comprises 36 valid species distributed in West, Central and East Africa. The available cytogenetic information for the genus indicates a wide variability in diploid chromosome number (2n) and number of chromosome arms (FN). Here, we report the karyotype of Epiplatys spilargyreius (Duméril, 1861), one of the two species with the lowest diploid chromosome number (2n = 34) in the genus, from the White Nile basin in Ethiopia. Male and female karyotypes contained 18 metacentric/acrocentric and 16 subtelocentric/acrocentric chromosomes. The number of chromosome arms is, respectively, FN = 52. Analysis of karyotype differentiation in the genus allowed us to suggest that the 2n reduction in E. spilargyreius and many other members of the genus Epiplatys is mainly due to Robertsonian translocations (reduction of 2n from 48 to 34 with stable NF = 48–52). We provide an up-to-date summary of cytogenetic data and a brief review of chromosome evolution in the genus.

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DOI: 10.3897/compcytogen.19.153340

Authors: Le-Le He, Ying Miao, He-Hong Wang, Jie Zhang, Bao-Zhen Hua

Abstract: Supernumerary B chromosomes are significant dispensable genetic elements that follow their own species-specific evolutionary pathways. Despite their widespread occurrence, comprehensive analyses of their meiotic behavior remain limited. In this study, we present the first systematic investigation of B chromosome morphology and meiotic behavior in the hangingfly Bittacus cirratus Tjeder, 1956 using cytogenetic approaches. The male basal chromosome numbers of B. cirratus is 2n = 30 + XO, with 0–5 polymorphic B chromosomes. Intraspecific B chromosome polymorphism manifests as various distinct morphotypes ranging from punctiform, bicentric, and ring-shaped to larger coiled forms, indicating that the B chromosomes may undergo rapid structural changes. During meiosis, B chromosomes display transmission drive through asymmetric segregation, preferentially accumulating in one daughter cell. Most B chromosomes formed univalents, with few forming bivalents or trivalents at meiosis I. Three unconventional retention mechanisms were identified in univalent B chromosomes: (1) associating with a nonhomologous chromosome, (2) accumulating near spindle poles, and (3) contributing to unequal spindle formation. Based on the abundant chromosomal changes of A chromosomes and stable XX/XO sex determination, we infer that the B chromosomes likely originated from multiple A chromosomes in B. cirratus. The roles of B chromosomes in the cell cycle and individual fitness are briefly discussed, and the evolutionary scenario is putatively put forward for the diversification of B chromosomes.

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DOI: 10.3897/compcytogen.19.146136

Authors: Yoshinori Takeuchi, Koji Iizuka, Tadashi Nakazato, Hiroyuki Koishi, Hidehiro Hoshiba

Abstract: We analyzed chromosomes of four species of fishflies (Megaloptera: Chauliodinae). Three species were from western North America (Dysmicohermes disjunctus (Walker, 1866), Dysmicohermes ingens Chandler, 1954, and Orohermes crepusculus (Chandler, 1954)), and another one from eastern North America (Nigronia serricornis (Say, 1824)). The chromosome number of the three western species was 2n = 22, with the karyotype consisting of 10 pairs of autosomes plus XY in males. The X chromosomes of these three species are subtelocentric, while the Y chromosomes are small and dot-like. Of the ten pairs of autosomes, the last pair is substantially smaller than the others. The chromosome number in the first meiotic metaphase in spermatocytes of N. serricornis from Michigan was n = 10 (9 autosomal bivalents + Xyp in the male). The sex chromosomes of N. serricornis formed parachute-type bivalents synchronously with the autosomes. The parachute-type bivalent Xyp has also been found in four fishflies and four dobsonflies (Megaloptera: Corydalinae) from East Asia, as well as in a fishfly and a dobsonfly from North America. These data suggest that the two subfamilies of Corydalidae share a common sex-bivalent mechanism, along with many beetles (Coleoptera).

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DOI: 10.3897/compcytogen.19.146501

Authors: Yoshinori Takeuchi, Koji Iizuka, Hiroyuki Koishi, Hidehiro Hoshiba

Abstract: We analyzed chromosomes of four species of East Asian dobsonflies (Megaloptera: Corydalidae): Protohermes grandis (Thunberg, 1781), P. immaculatus Kuwayama, 1964, P. disjunctus Liu, Hayashi et Yang, 2007 and P. costalis (Walker, 1853). The chromosome number in all species was 2n = 24, consisting of 11 pairs of autosomes plus the XX chromosomes in females and the Xyp in males. The karyotype of P. immaculatus which occurs in near the central part of the Ryukyu Islands, and is a vicarious species of P. grandis, was similar to the karyotype of P. grandis. On the other hand, the karyotype of P. disjunctus, which is from the Sakishima Islands, and is a vicarious species of P. costalis, resembled that of P. costalis. The X chromosomes are submetacentric, while the Y is the smallest, dot-like chromosome of the set. The sex chromosomes of the first meiotic metaphase (MI) spermatocytes in all species invariably appear as a bivalent-like structure known as parachut bivalents Xyp, suggesting that the species in this genus share a common sex-bivalent mechanism.

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DOI: 10.3897/compcytogen.19.141735

Authors: Veronika V. Golygina, Andrey D. Broshkov, Oksana V. Ermolaeva

Abstract: Chromosomal polymorphism has been studied in 31 natural populations of Ch. borokensis. For 11 out of 31 populations quantitative analysis of chromosomal polymorphism has been performed. Data from previous publications (10 populations) have also been used to perform an overview of the chromosomal polymorphism of Ch. borokensis and to establish the species range. Most studied populations show a high level of chromosomal polymorphism: on average 66.1 ± 2.6% of specimens were heterozygotes with 1.1 ± 0.6 heterozygotic inversions per larvae. The number of banding sequences found in populations varied from 7 to 18 per population with an average of 12 ± 3. Inversions were found in all chromosomal arms. Besides inversions, B-chromosome was present in 13 populations, and 5 translocations were found. The total number of banding sequences found in banding sequence pool of Ch. borokensis is 40. Twenty six banding sequences are described for the first time for the species.

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DOI: 10.3897/compcytogen.19.141557

Authors: Phichaya Buasriyot, Weerayuth Supiwong, Nawarat Muanglen, Nattasuda Donbundit, Sukhonthip Ditcharoen, Phonluang Chumpol, Pasakorn Saenjundaeng, Sampan Tongnunui, Sathit Arunsang, Weera Thongnetr, Sitthisak Juntharat, Kriengkrai Seetapan, Thomas Liehr, Marcelo B. Cioffi, Petr Rab, Alongklod Tanomtong

Abstract: The barbels of the subfamilies ´Poropuntinae´ and Smiliogastrinae within the family Cyprinidae play a significant role as a food source for fish in artisanal fisheries and are highly valued as ornamental fish in Thailand. In this study, we employed both conventional and molecular cytogenetics to analyze the karyotype of 15 fish species from two cyprinid lineages. All analyzed species had a diploid chromosome number of 2n = 50. Despite sharing the same 2n, our analyses revealed species-specific distribution patterns of the mapped microsatellite motifs [(CA)₁₅, (TA)₁₅, (CAC)₁₀, and (CGG)₁₀]. They were predominantly found at telomeric sites of all-to-few chromosomes. Additionally, some species exhibited a widespread distribution of the mapped microsatellites across the chromosomes while others showed no signal. These variations reflect the evolutionary divergence and chromosomal diversity within the cyprinids. Thus, our findings support the 2n stability in cyprinoid lineages while emphasizing the intrachromosomal evolutionary diversity accompanied by species-specific microsatellite distribution.

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DOI: 10.3897/compcytogen.19.132971

Authors: Brendan Mobley, Andrew P. Anderson

Abstract: Identifying clades with extensive and conspicuous changes in diploid chromosome number (2n) is an important step in unraveling the evolutionary mechanisms underlying karyotype evolution. Here, we report low 2n in a monophyletic group of teleost fishes within the family Osphronemidae defined by their unique spiral egg structure (the “spiral egg” clade). We sampled seven of the nine known species within the spiral egg clade, reporting novel 2n for five species and confirming two others. We find high variability in both 2n and chromosome arm number (fundamental number, FN), suggesting a 2n reduction during the emergence of the clade and numerous large-scale mutations across evolutionary time. These data provide important information in cataloguing 2n shifts in teleost fishes and highlight this group for further study in chromosomal and genomic evolution due to their karyotypic heterogeneity.

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DOI: 10.3897/compcytogen.19.142613

Authors: Vladimir A. Lukhtanov

Abstract: Despite recent advances in telomere research, the telomere DNA organization remains unknown for representatives of several insect orders. In this study, analysis of the chromosome-level genome assembly shows that the telomeric DNA of the earwig Labia minor (Linnaeus, 1758) (Polyneoptera, Dermaptera, Spongiphoridae) consists of repeats of the 5 bp motif TTCGG/CCGAA. This is the first record describing the structure of telomeric DNA in the order Dermaptera. This record expands the spectrum of the known telomeric sequences, since the TTCGG motif has not been reported for insects previously.

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DOI: 10.3897/compcytogen.19.135127

Authors: Manolo Penitente, Caio Augusto Gomes Goes, Rodrigo Zeni dos Santos, Ricardo Utsunomia, Fausto Foresti, Fabio Porto-Foresti

Abstract: The fish species Prochilodus lineatus has an interesting B chromosome system, with three morphological types as acrocentric, metacentric, and submetacentric. However, most cytogenetic studies on this species are restricted to the natural population of the Mogi Guaçu River. Given this, the present work aimed to study the structure karyotypic profile as well as the occurrence of supernumeraries in P. lineatus in several localities in the Paraná River basin, where this species is abundant. The results obtained showed a predominantly conserved karyotypic macrostructure and the presence of B chromosomes in all the seven localities studied, with the exception of the Apa River. Additionally, new variants of morphological characteristics were found in the population of the Batalha River (Reginópolis). These results allow us to infer that there is a large occurrence of B chromosomes in this species, with important differences in B chromosome frequency between the populations, especially in acrocentric and submetacentric B variants. Considering the possible origin and evolution of B chromosomes in P. lineatus, our results allow us to describe the dispersion of metacentric B variants, in contrast with the elimination observed in acrocentric and submetacentric variants.

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DOI: 10.3897/compcytogen.18.143444

Authors: Ilya A. Gavrilov-Zimin

Abstract: Without abstract

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DOI: 10.3897/compcytogen.18.138747

Authors: Valentina Kuznetsova, Paraskeva Michailova, Andrey Przhiboro, Natalia Khabazova

Abstract: The article is dedicated to the memory of Dr. Sc. Ninel A. Petrova, who passed away on 18 April 2024, and to her scientific heritage. Ninel was born on 28 March 1940 in Leningrad, the former Soviet Union. From 1959 to 1964, she studied at the Faculty of Biology and Soil Science of the Leningrad State University. After graduating from the university, Ninel joined the Zoological Institute of the Russian Academy of Sciences, where she worked for almost 60 years, rising from a research assistant to a leading researcher. Her scientific research focused on the structure and evolution of polytene chromosomes of two families of Diptera, black flies (Simuliidae) and non-biting midges (Chironomidae). Ninel has published nearly 200 scientific articles, three monographs and one monograph chapter and has become one of the leading experts in her field. Along with scientific activities, Ninel worked for 25 years as the Scientific Secretary of the Specialized Scientific Council for the Defense of Dissertations at the Zoological Institute.

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DOI: 10.3897/compcytogen.18.136095

Authors: Ilya A. Gavrilov-Zimin

Abstract: The paper elaborates theoretical basis of the origin of aphid cyclical parthenogenesis in view of the original life of these insects in strobiloid galls on Picea spp. The period of gall opening is greatly extended in time, which prevents normal panmixia and creates a selective advantage for parthenogenetic reproduction. Migration of aphids to secondary host plants, on which closed galls never form, parthenogenetic reproduction on these plants, and the subsequent simultaneous return of “remigrants” to the main host plant make it possible to synchronize the development of the bisexual generation and achieve mass panmixia at the end of the life cycle only; it coincides with the end of summer growth shoots or the autumn end of the vegetation period as a whole. The evolutionary transition of aphids from conifers to angiosperms in the Cretaceous period in parallel meant the possibility of development in more spacious galls accommodating several consecutive parthenogenetic generations, the transition to viviparity and telescopic embryonization, significantly accelerating the propagation.

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DOI: 10.3897/compcytogen.18.142301

Authors: Vladimir E. Gokhman, Valentina G. Kuznetsova, Boris A. Anokhin

Abstract: To identify nucleolus organizing regions (NORs), fluorescence in situ hybridization (FISH) with 18S rDNA probe was performed on chromosomes of Tenthredo campestris Linnaeus, 1758 (Tenthredinidae), Arge ciliaris (Linnaeus, 1767) (Argidae) (n = 10 in both) and Aulacidea hieracii (Bouché, 1834) (Cynipidae) (2n = 20). In all these species, a single pericentromeric rDNA cluster per haploid karyotype was detected. This number of NORs is confirmed as ancestral for the order Hymenoptera.

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DOI: 10.3897/compcytogen.18.135056

Authors: Yasmine Kartout-Benmessaoud, Siham Ouchia-Benissad, Leila Mahiddine-Aoudjit, Kafia Ladjali-Mohammedi

Abstract: Birds are one of the most diverse groups among terrestrial vertebrates. They evolved from theropod dinosaurs, are closely related to the sauropsid group and separated from crocodiles about 240 million years ago. According to the IUCN, 12% of bird populations are threatened with potential extinction. Classical cytogenetics remains a powerful tool for comparing bird genomes and plays a crucial role in the preservation populations of endangered species. It thus makes it possible to detect chromosomal abnormalities responsible for early embryonic mortalities. Thus, in this work, we have provided new information on part of the evolutionary history by analysing high-resolution GTG-banded chromosomes to detect inter- and intrachromosomal rearrangements in six species. Indeed, the first eight autosomal pairs and the sex chromosomes of the domestic fowl Gallus gallus domesticus Linnaeus, 1758 were compared with five species, four of which represent the order Galliformes (Common and Japanese quail, Gambras and Chukar partridge) and one Otidiformes species (Houbara bustard). Our findings suggest a high degree of conservation of the analysed ancestral chromosomes of the four Galliformes species, with the exception of (double, terminal, para and pericentric) inversions, deletion and the formation of neocentromeres (1, 2, 4, 7, 8, Z and W chromosomes). In addition to the detected rearrangements, reorganisation of the Houbara bustard chromosomes mainly included fusions and fissions involving both macro- and microchromosomes (especially on 2, 4 and Z chromosomes). We also found interchromosomal rearrangements involving shared microchromosomes (10, 11, 13, 14 and 19) between the two analysed avian orders. These rearrangements confirm that the structure of avian karyotypes will be more conserved at the interchromosomal but not at intrachromosomal scale. The appearance ofa small number of inter- and intrachromosomal rearrangements that occurred during evolution suggests a high degree of conservatism of genome organisation in these six species studied. A summary diagram of the rearrangements detected in this study is proposed to explain the chronology of the appearance of various evolutionary events starting from the ancestral karyotype.

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DOI: 10.3897/compcytogen.18.133534

Authors: Vladimir E. Gokhman, María Gabriela Luna, Consuelo Vallina, María José Bressa

Abstract: The karyotype of Pseudapanteles dignus (Muesebeck, 1938), an important parasitoid of a serious tomato pest Phthorimaea (= Tuta) absoluta Meyrick, 1917 (Lepidoptera, Gelechiidae), in the Neotropics and adjacent regions, was studied for the first time using morphometric analysis and several techniques of differential chromosome staining, i.e., C-banding and staining with base-specific fluorochromes, together with fluorescence in situ hybridization (FISH) with an 18S rDNA probe. We found n = 7 and 2n = 14 in P. dignus, with seven metacentric chromosomes of similar size in the haploid set. C-banding revealed various C-positive bands, either centromeric or interstitial, on most chromosomes. Both AT-specific and GC-specific fluorochromes, 4’6-diamidino-2-phenylindole (DAPI) and chromomycin A3 (CMA3) respectively, showed uniform staining of chromosomes. FISH visualized a single subterminal rDNA site on a medium-sized metacentric. A brief review of known chromosome sets of the subfamily Microgastrinae (Braconidae) is given; certain features of karyotype evolution of this group are discussed.

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DOI: 10.3897/compcytogen.18.127373

Authors: Alina Zhukova, Gennadii Zakharov, Olga Pavlova, Alsu Saifitdinova

Abstract: Ribosomal RNA (18S, 5.8S, 28S) gene clusters in genomes form regions that consist of multiple tandem repeats. They are located on a single or several pairs of chromosomes and play an important role in the formation of the nucleolus responsible for the assembly of ribosome subunits. The rRNA gene cluster sequences are widely used for taxonomic studies, however at present, complete information on the avian rDNA repeat unit structure including intergenic spacer sequence is available only for the chicken (Gallus gallus domesticus Linnaeus, 1758). The GC enrichment and high-order repeats peculiarities within the intergenic spacer described for the chicken rDNA cluster may be responsible for these failures. The karyotype of the Japanese quail (Coturnix japonica Temminck et Schlegel, 1849) deserves close attention because, unlike most birds, it has three pairs of nucleolar organizer bearing chromosomes, two of which are microchromosomes enriched in repeating elements and heterochromatin that carry translocated terminal nucleolar organizers. Here we assembled and annotated the complete Japanese quail ribosomal gene cluster sequence of 21166 base pairs (GenBank under the registration tag BankIt2509210 Coturnix OK523374). This is the second deciphered avian rDNA cluster after the chicken. Despite the revealed high similarity with the chicken corresponding sequence, it has a number of specific features, which include a slightly lower degree of GC content and the presence of bendable elements in the content of both the transcribed spacer I and the non-transcribed intergenic spacer.

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DOI: 10.3897/compcytogen.18.135172

Authors: Lorenzo Peruzzi, Jacopo Franzoni, Manuel Tiburtini, Emanuela Abidi, Emiliano Alù, Giulio Barone, Elisabetta Bianchi, Chiara Cataudella, Emanuela Di Iorio, Maria Guerrina, Fabio Mondello, Luca Paino, Mario Pentassuglia, Manuela Porrovecchio, Giovanni Rivieccio, Eugenia Siccardi, Adriano Stinca, Alessio Tei, Virginia Volanti, Antonio Giacò

Abstract: Within a practical course of cytotaxonomy organized in Pisa (Italy) on February 2024 by the Group for Floristics, Systematics and Evolution of the Italian Botanical Society, we tested whether using image analysis softwares possible biases are still introduced by different observers. We conclude that observer bias selectively applies in possibly overestimating the length of short arms in a karyotype. As a consequence, the parameters most sensitive to these possible errors are CVCI and CVCL, and to a less degree MCA and THL. To achieve more stable results among observers, a still lacking standardized measurement protocol could be helpful.

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DOI: 10.3897/compcytogen.18.129133

Authors: Richard Mollard, Michael Mahony, Matt West

Abstract: The karyotype of Litoria (L.) paraewingi (Watson et al., 1971) (Big River State Forest, Victoria) is described here for the first time. It is prepared following tissue culture of toe clipping macerates, cryopreservation, reculture and conventional 4’,6-diamidino-2-phenylindole (DAPI) staining. The L. paraewingi karyotype is then compared to similarly processed IUCN (International Union for the Conservation of Nature) least concern members L. ewingii (Duméril et Bibron, 1841) (southern Victoria) and L. jervisiensis (Duméril et Bibron, 1841) (Myall Lakes National Park, New South Wales), all members of the same L. ewingii complex/group. The L. paraewingi diploid number is 2n = 26, the same as for the other two species. Litoria paraewingi chromosomes 1, 2, 6 and 7 are submetacentric, chromosomes 3 and 5 are subtelocentric and the remainder are metacentric. No secondary constriction or putative nucleolus organiser region (NOR) was readily identifiable following conventional DAPI staining in any scored L. paraewingi metaphase spread. Conversely, a putative NOR was readily identifiable on the long arm of chromosome 1 in all examined metaphase spreads for the other two species. The karyotypes of L. ewingii and L. jervisiensis here further differ from L. paraewingi with chromosome 1 being metacentric and chromosomes 8 and 10 being submetacentric for both former species. The L. jervisiensis karyotype differs from those of L. ewingii and L. paraewingi by DAPI staining with: (i) apparent relative length inversion of subtelocentric chromosome 3 and metacentric chromosome 4 and (ii) chromosome 6 being metacentric rather than submetacentric. All three species have a highly conserved chromosome morphology with respect to chromosomes 2, 5, 7, 9, 11, 12 and 13. The greatest gross morphological difference karyotypically is observed between L. paraewingi and L. jervisiensis. These karyotype data support the previous phylogenetic separation of these three species based upon genetic compatibility and behavioural, biochemical and molecular genetic analyses.

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DOI: 10.3897/compcytogen.18.119929

Authors: Wen Bao Ma, Yafei Ou, Buddhi Dayananda, Hui Juan Ji, Tao Yu

Abstract: Rhododendron Linnaeus, 1753, the largest genus of woody plants in the Northern Hemisphere, includes some of the most significant species in horticulture. Rhododendron ambiguum Hemsl, 1911, a member of subsection Triflora Sleumer 1947, exemplifies typical alpine Rhododendron species. The analysis of the complete chloroplast genome of R. ambiguum offers new insights into the evolution of Rhododendron species and enhances the resolution of phylogenetic relationships. This genome is composed of 207,478 base pairs, including a pair of inverted repeats (IRs) of 47,249 bp each, separated by a large single-copy (LSC) region of 110,367 bp and a small single-copy (SSC) region of 2,613 bp. It contains 110 genes: 77 protein-coding genes, 29 tRNAs, four unique rRNAs (4.5S, 5S, 16S, and 23S), with 16 genes duplicated in the IRs. Comparative analyses reveal substantial diversity in the Rhododendron chloroplast genome structures, identifying a fourth variant pattern. Specifically, four highly divergent regions (trnI-rpoB, ndhE-psaC, rpl32-ndhF, rrn16S-trnI) were noted in the intergenic spacers. Additionally, 76 simple sequence repeats were identified. Positive selection signals were detected in four genes (cemA, rps4, rpl16, and rpl14), evidenced by high Ka/Ks ratios. Phylogenetic reconstruction based on two datasets (shared protein-coding genes and complete chloroplast genomes) suggests that R. ambiguum is closely related to R. concinnum Hemsley, 1889. However, the phylogenetic positions of subsection Triflora Pojarkova, 1952 species remain unresolved, indicating that the use of complete chloroplast genomes for phylogenetic research in Rhododendron requires careful consideration. Overall, our findings provide valuable genetic information that will enhance understanding of the evolution, molecular biology, and genetic improvement of Rhododendron spieces.

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DOI: 10.3897/compcytogen.18.126130

Authors: Viktor Bolshakov, Alexander Prokin, Elena Ivanova, Ekaterina Movergoz

Abstract: Chironomus nuditarsis Keyl, 1961 is recorded from Sevan Lake for the first time. This species is widespread in Europe, the Caucasus, and Siberia. For species identification, we used a comprehensive approach that included morphological, cytogenetic and molecular genetic analyses. Morphological analysis showed a high similarity with the description. Nine chromosome banding sequences ndtA1, ndtA2, ndtB2, ndtC1, ndtD1, ndtE1, ndtF1, ndtG1, and ndtG2 were found. The banding sequences ndtA1, ndtA2, ndtG1, and ndtG2 are species-specific for C. nuditarsis and allow us to accurately distinguish it from the sibling species Ch. curabilis Belyanina, Sigareva et Loginova, 1990. Molecular-genetic analysis of the COI gene sequences has shown low genetic distances of 0.38–0.95% in the sibling species Ch. nuditarsis and Ch. curabilis complex and the insufficiency of using a single COI as a molecular marker for their separation.

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DOI: 10.3897/compcytogen.18.125235

Authors: Monique Telcia dos Santos Damasceno, Gisele Amaro Teixeira, Paulo Castro Ferreira, Rodrigo Batista Lod, Luísa Antônia Campos Barros, Hilton Jeferson Alves Cardoso de Aguiar

Abstract: Recently, hypotheses regarding the evolutionary patterns of ribosomal genes in ant chromosomes have been under discussion. One of these hypotheses proposes a relationship between chromosomal location and the number of rDNA sites, suggesting that terminal locations facilitate the dispersion of rDNA clusters through ectopic recombination during meiosis, while intrachromosomal locations restrict them to a single chromosome pair. Another hypothesis suggests that the multiplication of rDNA sites could be associated with an increase in the chromosome number in Hymenoptera due to chromosomal fissions. In this study, we physically mapped rDNA sites in 15 new ant species and also reviewed data on rDNA available since the revision by Teixeira et al. (2021a). Our objectives were to investigate whether the new data confirm the relationship between chromosomal location and the number of rDNA sites, and whether the increase in the chromosome number is significant in the dispersion of rDNA clusters in ant karyotypes. Combining our new data with all information on ant cytogenetics published after 2021, 40 new species and nine new genera were assembled. Most species exhibited intrachromosomal rDNA sites on a single chromosome pair, while three species showed these genes in terminal regions of multiple chromosome pairs. On one hand, the hypothesis that the chromosomal location of rDNA clusters may facilitate the dispersion of rDNA sites in the ant genome, as previously discussed, was strengthened, but, on the other hand, the hypothesis of chromosomal fission as the main mechanism for dispersion of ribosomal genes in ants is likely to be refuted. Furthermore, in certain genera, the location of rDNA sites remained similar among the species studied, whereas in others, the distribution of these genes showed significant variation between species, suggesting a more dynamic chromosomal evolution.

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DOI: 10.3897/compcytogen.18.116806

Authors: Liaoruilin Zhang, Jianguo Xiang, Juan Li, Jie Zhou, Jinliang Hou, Yanfei Huang, Hong Li

Abstract: The current study analyzed the chromosomal karyotype of Quasipaa spinosa David, 1875 from Hunan Province, China. The karyotype, C-banding, BrdU-banding pattern were characterized using direct preparation of bone-marrow cells and hemocyte cultures. The findings indicated that Q. spinosa was a diploid species (2n = 26) that lacked heteromorphic chromosomes and secondary constrictions. C-banding analysis revealed an abundance of positive signals in the centromere regions, while the BrdU-banding pattern showed three phases in both male and female, occurring consistently and in chronological sequence during S-phase. Notably, there was no asynchronous replication in the late phase. This study enhanced our understanding of the karyotypic structure of Q. spinosa by conventional cytogenetic techniques, thus providing essential scientific insights into the cytogenetics of Q. spinosa.

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DOI: 10.3897/compcytogen.18.122399

Authors: Yan-Fang Wei, Xiang-Hui Jiang, Rong Song, Chao-Wen She

Abstract: To characterize the chromosomes of the four species of Polygonatum Miller, 1754, used in traditional Chinese medicine, P. cyrtonema Hua, 1892, P. kingianum Collett et Hemsley, 1890, P. odoratum (Miller, 1768) Druce, 1906, and P. sibiricum Redouté, 1811, and have an insight into the karyotype variation of the genus Polygonatum, fluorescence in situ hybridization (FISH) with 5S and 45S rDNA oligonucleotide probes was applied to analyze the karyotypes of 9 populations of the four species. Detailed molecular cytogenetic karyotypes of the 9 populations were established for the first time using the dataset of chromosome measurements and FISH signals of 5S and 45S rDNA. Four karyotype asymmetry indices, CVCI, CVCL, MCA and Stebbins’ category, were measured to elucidate the asymmetry of the karyotypes and karyological relationships among species. Comparison of their karyotypes revealed distinct variations in the karyotypic parameters and rDNA patterns among and within species. The basic chromosome numbers detected were x = 9, 11 and 13 for P. cyrtonema, x = 15 for P. kingianum, x = 10 and 11 for P. odoratum, and x = 12 for P. sibiricum. The original basic chromosome numbers of the four species were inferred on the basis of the data of this study and previous reports. All the 9 karyotypes were of moderate asymmetry and composed of metacentric, submetacentric and subtelocentric chromosomes or consisted of two of these types of chromosomes. Seven populations have one locus of 5S rDNA and two loci of 45S rDNA, and two populations added one 5S or 45S locus. The karyological relationships among the four species revealed by comparison of rDNA patterns and PCoA based on x, 2n, TCL, CVCI, MCA and CVCL were basically accordant with the phylogenetic relationships revealed by molecular phylogenetic studies. The mechanisms of both intra- and inter-specific dysploidy in Polygonatum were discussed based on the data of this study and literature.

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DOI: 10.3897/compcytogen.18.117597

Authors: Natália Padilha de Oliveira, Gabriel de Siqueira Gesteira, Maria do Socorro Padilha de Oliveira, Lisete Chamma Davide

Abstract: The genus Oenocarpus Martius, 1823 (Arecaceae) includes five species commonly used in Amazonia, especially for their fruits. Little is known about the cytogenetic characteristics and DNA amounts of these species, except for O. bataua (Martius, 1823). This study characterized and compared the types of interphase nuclei, the chromosome sets, and estimated the nuclear DNA amounts of Oenocarpus bacaba (Martius, 1823), O. bataua, O. distichus (Martius, 1823), O. mapora (H. Karsten, 1857) and O. minor (Martius, 1823). Standard cytogenetic analyses and estimates of the nuclear DNA amount by flow cytometry were carried out. These are the first reports of chromosome numbers and DNA amounts, except for O. bataua, as is the description of the chromatin distribution in interphase nuclei and karyotype for all species. All species presented 2n = 36, confirming the previous report for O. bataua. Differences between karyotype formulas and the positioning of secondary constrictions were observed. There were no significant differences for the nuclear DNA amounts among species. The constancy in chromosome number and variations in karyotype formulas suggest the occurrence of chromosome rearrangement as an important mechanism in Oenocarpus speciation.

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DOI: 10.3897/compcytogen.18.121459

Authors: Natalia N. Bezborodkina, Vsevolod Ya. Brodsky, Boris N. Kudryavtsev

Abstract: Polyploidy is a condition in which a cell has multiple diploid sets of chromosomes. Two forms of polyploidy are known. One of them, generative polyploidy, is characteristic of all cells of the organism, while the other form develops only in some somatic tissues at certain stages of postnatal ontogenesis. Whole genome duplication has played a particularly important role in the evolution of plants and animals, while the role of cellular (somatic) polyploidy in organisms remains largely unclear. In this work we investigated the contribution of cellular polyploidy to the normal and the reparative liver growth of Rattus norvegicus (Berkenhout, 1769) and Homo sapiens Linnaeus, 1758. It is shown that polyploidy makes a significant contribution to the increase of the liver mass both in the course of normal postnatal development and during pathological process.

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DOI: 10.3897/compcytogen.17.112152

Authors: Andrey Grishanin

Abstract: This work reveals the opportunities to obtain additional information about some biological problems through studying species that possess chromatin diminution. A brief review of the hypothesized biological significance of chromatin diminution is discussed. This article analyzes the biological role of chromatin diminution as it relates to the C-value enigma. It is proposed to consider chromatin diminution as a universal mechanism of genome reduction, reducing the frequency of recombination events in the genome, which leads to specialization and adaptation of the species to more narrow environmental conditions. A hypothesis suggesting the role of non-coding DNA in homologous recombination in eukaryotes is proposed. Cyclops kolensis Lilljeborg, 1901 (Copepoda, Crustacea) is proposed as a model species for studying the mechanisms of transformation of the chromosomes and interphase nuclei structure of somatic line cells due to chromatin diminution. Chromatin diminution in copepods is considered as a stage of irreversible differentiation of embryonic cells during ontogenesis. The process of speciation in cyclopoids with chromatin diminution is considered.

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DOI: 10.3897/compcytogen.18.115784

Authors: Alexander Bugrov, Tatyana Karamysheva, Olesya Buleu

Abstract: This study provides data on chromosome number (2n♂♀=26), sex determination mechanism (XY♂/XX♀), C-banding pattern, distribution of clusters of telomeric TTAGG repeats and 18S ribosomal DNA in the karyotype of the stonefly Skwala compacta (McLachlan, 1872). For the first time in the history of stoneflies cytogenetics, we provide photos of the chromosomes of the Plecoptera insects. The karyotype of males and females of S. compacta consists of 12 pairs of autosomes. Three pairs of large autosomes and four pairs of medium-sized autosomes are subacrocentric. The remaining pairs of autosomes are small, with unclear morphology. Pericentromeric C-bands were revealed in all autosomes. The sex chromosomes are also subacrocentric. The short arms of X and Y chromosomes are entirely heterochromatic and are rich in ribosomal DNA sequences. In the X chromosome this arm is larger than in the Y chromosome. It is likely that this arm associated with the nucleolar organizer (NOR). Telomeric DNA (TTAGG)n repeats were detected in the terminal regions of all chromosomes.

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DOI: 10.3897/compcytogen.18.115070

Authors: Ziravard N. Tonyan, Irina L. Puppo, Alsu F. Saifitdinova, Tatyana V. Vavilova, Andrey S. Glotov

Abstract: Patterns of meiotic chromosome segregation were analyzed in cleavage stage and blastocyst stage human embryos from couples with autosomal reciprocal translocations (ART). The influence of quadrivalent asymmetry degree, the presence of terminal breakpoints, and the involvement of acrocentric chromosomes in the rearrangement were analyzed to evaluate their contribution to the formation of non-viable embryos with significant chromosomal imbalance due to pathological segregation patterns and to assess the selection of human embryos by the blastocyst stage. A selection of viable embryos resulting from alternate and adjacent-1 segregation and a significant reduction in the detection frequency of the 3 : 1 segregation pattern were observed in human embryos at the blastocyst stage. The presence of terminal breakpoints increased the frequency of 3 : 1 segregation and was also associated with better survival of human embryos resulting from adjacent-1 mode, reflecting the process of natural selection of viable embryos to the blastocyst stage. The demonstrated patterns of chromosome segregation and inheritance of a balanced karyotype in humans will contribute to optimizing the prediction of the outcomes of in vitro fertilization programs and assessing the risks of the formation of unbalanced embryos for ART carriers.

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DOI: 10.3897/compcytogen.17.115485

Authors: Vladimir E. Gokhman

Abstract: Results of the chromosome study of 12 sawfly species of the genus Arge Schrank, 1802 are reviewed, including new data on the karyotypes of A. ciliaris (Linnaeus, 1767) and A. enodis (Linnaeus, 1767) with n = 10. Moreover, the same chromosome number, n = 10, is found in A. ustulata (Linnaeus, 1758), for which n = 8 was previously reported. In addition, n = 8 is confirmed in A. gracilicornis (Klug, 1814). The results of the morphometric analysis of chromosome sets of these four species are given. In the genus Arge, haploid chromosome numbers of n = 8, 10, 11 and 13 were found. Among these sawflies, n = 8 appeared to be the most frequent chromosome number, followed by n = 10. The known data of the chromosome study of these insects are summarized and discussed in the light of phylogeny and taxonomy of the genus Arge.

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DOI: 10.3897/compcytogen.17.112831

Authors: Robert B. Angus

Abstract: An account is given of my development of techniques to obtain well-spread Giemsa-stained banded chromosome preparations. Apparent G-banding could be obtained following very slight trypsin treatment of freshly prepared slides, but this banding was very fine (close-grained) and possibly not a reflection of chromosome structure. However, treatment of developing embryos in vitro with 5-fluorouridine produced a similar chromomere banding, which is therefore regarded as genuine. Steady accumulation of Helophorus Fabricius, 1775 karyotypes has resulted in the production of an Atlas covering 62 of the 170 species known to occur in the Palaearctic. Chromosome polymorphisms involving pericentric inversions and addition of extra C-banding regions have been found, as well as small B-chromosomes in a few species. In general, karyotypes have proved very useful in establishing the limits of individual species. Parthenogenesis involving triploidy has been found in two species. Karyotypes of experimentally produced hybrids have revealed irregularities in chromosome condensation.

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DOI: 10.3897/compcytogen.17.116628

Authors: Natalia V. Golub, Boris A. Anokhin, Valentina G. Kuznetsova

Abstract: We studied the karyotype and chromosomal distribution of 18S rDNA clustered in nucleolar organizer regions (NORs) in Nysius graminicola (Kolenati, 1845), belonging to the subfamily Orsillinae (Lygaeidae). It is shown that this species has a karyotype with 2n = 22(18+mm+XY), previously known in only one of 24 studied species of the genus Nysius Dallas, 1852, characterized by a similar karyotype, 2n = 14(12+mm+XY). In N. graminicola, 18S loci are located on sex chromosomes, which is a previously unknown trait for this genus. Our results in a compilation with previous data revealed dynamic evolution of rDNA distribution in Nysius. It is concluded that molecular chromosomal markers detected by FISH contribute to a better understanding of the structure and evolution of the taxonomically complex genus Nysius.

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DOI: 10.3897/compcytogen.17.116550

Authors: Ilya A. Gavrilov-Zimin

Abstract: The karyotype and reproductive features of Orbuspedum machinator Gavrilov-Zimin, 2017 (Pseudococcidae) were studied for the first time. Diploid chromosome number is 18 in females. Reproduction is probably bisexual, as indicated by the presence of characteristic Lecanoid heterochromatinization of the paternal set of chromosomes in embryonic cells of about 50% of the embryos studied. The female reproductive system has a pair of lateral oviducts merged into enlarged common oviduct; the spermatheca and accessory glands are connected to the common oviduct in its proximal part. Complete ovoviviparity occurs in ontogenesis.

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DOI: 10.3897/compcytogen.17.108265

Authors: Doris Vela, Erika Villavicencio

Abstract: The mitotic metaphases of five Andean species of genus Drosophila are described for the first time. The evolutionary and interspecific genetic relationships within three Neotropical Drosophila species groups are analyzed. The diploid chromosome number for each species is as follows: D. cashapamba Céspedes et Rafael, 2012 2n = 6 (2V, 1J) (X = J, Y = R), D. ecuatoriana Vela et Rafael, 2004 2n = 10 (3R, 2V) (X = V, Y = R), D. ninarumi Vela et Rafael, 2005 2n = 10 (3R, 1V, 1D) (X = V, Y = R), D. urcu Vela et Rafael, 2005 2n = 12 (4R, 2V) (X = V, Y = R), D. valenteae Llangarí-Arizo et Rafael, 2018 2n = 8 (3R, 1J) (X = J, Y = R).

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DOI: 10.3897/compcytogen.17.113526

Authors: Richard Mollard, Michael Mahony

Abstract: The karyotype of the IUCN least concern red-backed toadlet Pseudophryne (P.) coriacea (Keferstein, 1868) from the New South Wales Central Coast is described following tissue culture of toe clipping macerates and conventional DAPI staining. The diploid number is 2n = 24. The karyotype is represented by six large and five small chromosomal pairs and one very small chromosomal pair. The very small chromosome 12 is 12% the size of chromosome 1. One of the large chromosomes is subtelocentric, two of the large chromosomes are submetacentric and the remaining chromosomes are metacentric. The putative nucleolus organiser region (NOR) is observed on chromosome 4. The diploid number and location of the putative NOR correlates to that of the previously published IUCN critically endangered P. corroboree (Moore 1953) and unpublished descriptions of the P. coriacea karyotype. This is the first described cell culture of a species from the genus Pseudophryne Fitzinger, 1843, first published analysis of the P. coriacea karyotype and the first published analysis of centromeric allocation of this genus. Globally there exists a large inventory of tissue samples in cryobanks that are not associated with known recovery mechanisms such as basic cell culture techniques. Detailed cytogenetic analyses of these cryobanked samples are therefore not possible. This work therefore enables: (i) a comparison of the P. coriacea karyotype with that of the critically endangered P. corroboree and (ii) a benchmark for repeat and future cytogenetic and genomic analyses of cryostored samples of this genus.

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DOI: 10.3897/compcytogen.17.107744

Authors: Sergey A. Simanovsky, Dmitry A. Medvedev, Fekadu Tefera, Alexander S. Golubtsov

Abstract: The African family Distichodontidae comprises 109 species in 16 genera. Up-to-date cytogenetic information was available for the only distichodontid species Distichodus affinis Günther, 1873. Here we report chromosome number and morphology in: Distichodus engycephalus Günther, 1864 (2n = 52, FN = 104), Ichthyborus besse (Joannis, 1835) (2n = 46, FN = 92), Nannocharax niloticus (Joannis, 1835) (2n = 54, FN = 106) and three taxa, Nannaethiops bleheri Géry et Zarske, 2003, Nannaethiops sp., and Neolebias unifasciatus Steindachner, 1894, that exhibit the same karyotypes (2n = 50, FN = 98). To confirm the Nannaethiops Günther, 1872 and Neolebias Steindachner, 1894 species identification, mt-DNA sequences of the two markers (COI and 16S rRNA) were obtained from karyotyped specimens and compared with the relevant sequences accessible from GenBank. The great prevalence of biarmed chromosomes (the karyotypes of most species contain exclusively biarmed chromosomes) is a distinctive characteristic of Distichodontidae and Cithariniformes as a whole.

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DOI: 10.3897/compcytogen.17.112332

Authors: Vladimir E. Gokhman

Abstract: A brief overview of the current stage of the chromosome study of the insect order Hymenoptera is given. It is demonstrated that, in addition to routine staining and other traditional techniques of chromosome research, karyotypes of an increasing number of hymenopterans are being studied using molecular methods, e.g., staining with base-specific fluorochromes and fluorescence in situ hybridization (FISH), including microdissection and chromosome painting. Due to the advent of whole genome sequencing and other molecular techniques, together with the “big data” approach to the chromosomal data, the current stage of the chromosome research on Hymenoptera represents a transition from Hymenoptera cytogenetics to cytogenomics.

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DOI: 10.3897/compcytogen.17.109671

Authors: Ilya A. Gavrilov-Zimin

Abstract: It is demonstrated that the initial method of fertilization in animals (Metazoa), embryophyte plants (Embryophyta), most groups of multicellular oogamous algae, oogamous and pseudoogamous multicellular fungi was internal fertilization (in the broad meaning) in/on the body of a maternal organism. Accordingly, during the bisexual process, the initial method of formation of a daughter multicellular organism in animals was viviparity, and in embryophyte plants and most groups of oogamous multicellular algae – the germination of a zygote in/on the body of maternal organism. The reproductive criteria of multicellularity are proposed and discussed. In this regard, the multicellularity is considered to subdivide terminologically into three variants: 1) protonemal, the most simple, characteristic of multicellular prokaryotes, most groups of multicellular algae and gametophytes of some higher plants; 2) siphonoseptal, found among multicellular fungi, some groups of green and yellow-green algae; 3) embryogenic, most complicated, known in all animals (Metazoa), all sporophytes and some gametophytes of higher plants (Embryophyta), charophyte green algae Charophyceae s.s., oogamous species of green and brown algae, some genera of red algae. In addition to the well-known division of reproduction methods into sexual and asexual, it is proposed to divide the reproduction of multicellular organisms into monocytic (the emergence of a new organism from one cell sexually or asexually) and polycytic (fragmentation, longitudinal / transverse division or budding based on many cells of the body of the mother organism), since these two ways have different evolutionary and ontogenetic origins.

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DOI: 10.3897/compcytogen.17.107703

Authors: Sudarat Khensuwan, Weerayuth Supiwong, Chatmongkon Suwannapoom, Phichaya Buasriyot, Sitthisak Jantarat, Weera Thongnetr, Nawarat Muanglen, Puntivar Kaewmad, Pasakorn Saenjundaeng, Kriengkrai Seetapan, Thomas Liehr, Alongklod Tanomtong

Abstract: Cyprininae are a highly diversified but demonstrably monophyletic lineage of cypriniform fishes. Here, the karyotype and chromosomal characteristics of Hypsibarbus malcolmi (Smith, 1945) and H. wetmorei (Smith, 1931) were examined using conventional, nucleolus organizing regions (NORs) and molecular cytogenetic protocols. The diploid chromosome number (2n) of H. malcolmi was 50, the fundamental number (FN) was equal to 62, and the karyotype displayed 8m + 4sm + 38a with NORs located at the centromeric and telomeric positions of the short arms of chromosome pairs 1 and 2, respectively. 2n of H. wetmorei was 50, FN 78, karyotype 14m + 14sm + 22a with the NORs at the telomeric position of the short arm of chromosome pair 2. 2n and FN in males and females were identical. Fluorescence in situ hybridization using different microsatellite motifs as probes also showed substantial genomic divergence between both studied species. In H. wetmorei, (CAG)n and (CAC)n microsatellites accumulated in the telomeric regions of all chromosomes, while in H. malcolmi, they had scattered signals on all chromosomes. Besides, the (GAA)n microsatellites were distributed along all chromosomes of H. malcolmi, but there was a strong hybridization pattern in the centromeric region of a single pair in H. wetmorei. These cytogenomic difference across the genomes of these Hypsibarbus Rainboth, 1996 species are markers for specific evolutionary differentiation within these two species.

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DOI: 10.3897/compcytogen.17.101427

Authors: Zhiliang Li, Zhiwei Huang, Xuchun Wan, Jiaojun Yu, Hongjin Dong, Jialiang Zhang, Chunyu Zhang, Shuzhen Wang

Abstract: Rhododendron mariesii Hemsley et Wilson, 1907, a typical member of the family Ericaeae, possesses valuable medicinal and horticultural properties. In this research, the complete chloroplast (cp) genome of R. mariesii was sequenced and assembled, which proved to be a typical quadripartite structure with the length of 203,480 bp. In particular, the lengths of the large single copy region (LSC), small single copy region (SSC), and inverted repeat regions (IR) were 113,715 bp, 7,953 bp, and 40,918 bp, respectively. Among the 151 unique genes, 98 were protein-coding genes, 8 were tRNA genes, and 45 were rRNA genes. The structural characteristics of the R. mariesii cp genome was similar to other angiosperms. Leucine was the most representative amino acid, while cysteine was the lowest representative. Totally, 30 codons showed obvious codon usage bias, and most were A/U-ending codons. Six highly variable regions were observed, such as trnK-pafI and atpE-rpoB, which could serve as potential markers for future barcoding and phylogenetic research of R. mariesii species. Coding regions were more conserved than non-coding regions. Expansion and contraction in the IR region might be the main length variation in R. mariesii and related Ericaeae species. Maximum-likelihood (ML) phylogenetic analysis revealed that R. mariesii was relatively closed to the R. simsii Planchon, 1853 and R. pulchrum Sweet,1831. This research will supply rich genetic resource for R. mariesii and related species of the Ericaeae.

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DOI: 10.3897/compcytogen.17.103152

Authors: Eva Hnátková, Zuzana Majtánová, Vendula Bohlen Šlechtová, Joerg Bohlen, Petr Ráb

Abstract: The karyotype of the freshwater fish Sabanejewia bulgarica (Drensky, 1928), from the Danube Delta, was studied by conventional Giemsa staining and the C-banding technique. The diploid chromosome number was 2n = 50. The karyotype contained 2 pairs of metacentric (the first one was much larger than the second one), 6 pairs of submetacentric and 17 pairs of subtelocentric to acrocentric chromosomes. Pericentromeric blocks of heterochromatin were revealed in most of the chromosome pairs. The karyotype phenotype of S. bulgarica was the same as found for S. balcanica from Northern Carpathian Mountains.

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DOI: 10.3897/CompCytogen.17.98903

Authors: Biplab Kumar Bhowmick, Sayantika Sarkar, Dipasree Roychowdhury, Sayali D. Patil, Manoj M. Lekhak, Deepak Ohri, Satyawada Rama Rao, S. R. Yadav, R. C. Verma, Manoj K. Dhar, S. N. Raina, Sumita Jha

Abstract: The genus Allium Linnaeus, 1753 (tribe Allieae) contains about 800 species worldwide of which almost 38 species are reported in India, including the globally important crops (onion, garlic, leek, shallot) and many wild species. A satisfactory chromosomal catalogue of Allium species is missing which has been considered in the review for the species occurring in India. The most prominent base number is x=8, with few records of x=7, 10, 11. The genome size has sufficient clues for divergence, ranging from 7.8 pg/1C to 30.0 pg/1C in diploid and 15.16 pg/1C to 41.78 pg/1C in polyploid species. Although the karyotypes are seemingly dominated by metacentrics, substantial variation in nucleolus organizing regions (NORs) is noteworthy. The chromosomal rearrangement between A. cepa Linnaeus, 1753 and its allied species has paved way to appreciate genomic evolution within Allium. The presence of a unique telomere sequence and its conservation in Allium sets this genus apart from all other Amaryllids and supports monophyletic origin. Any cytogenetic investigation regarding NOR variability, telomere sequence and genome size in the Indian species becomes the most promising field to decipher chromosome evolution against the background of species diversity and evolution, especially in the Indian subcontinent.

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DOI: 10.3897/compcytogen.17.102830

Authors: Vazrick Nazari, Vladimir A. Lukhtanov, Alireza Naderi, Zdenek Faltýnek Fric, Vlad Dincă, Roger Vila

Abstract: A new subspecies of Leptidea sinapis from Northern Iran, discovered by means of DNA barcoding, is described as Leptidea sinapis tabarestana ssp. nov. The new subspecies is allopatric with respect to other populations of L. sinapis and is genetically distinct, appearing as a well-supported sister clade to all other populations in COI-based phylogenetic reconstructions. Details on karyotype, genitalia, ecology and behaviour for the new subspecies are given and a biogeographical speciation scenario is proposed.

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DOI: 10.3897/CompCytogen.17.101008

Authors: Ekaterina D. Badaeva, Violetta V. Kotseruba, Andnrey V. Fisenko, Nadezhda N. Chikida, Maria Kh. Belousova, Peter M. Zhurbenko, Sergei A. Surzhikov, Alexandra Yu. Dragovich

Abstract: Aegilops comosa Smith in Sibthorp et Smith, 1806 is diploid grass with MM genome constitution occurring mainly in Greece. Two morphologically distinct subspecies – Ae. c. comosa Chennaveeraiah, 1960 and Ae. c. heldreichii (Holzmann ex Boissier) Eig, 1929 are discriminated within Ae. comosa, however, genetic and karyotypic bases of their divergence are not fully understood. We used Fluorescence in situ hybridization (FISH) with repetitive DNA probes and electrophoretic analysis of gliadins to characterize the genome and karyotype of Ae. comosa to assess the level of their genetic diversity and uncover mechanisms leading to radiation of subspecies. We show that two subspecies differ in size and morphology of chromosomes 3M and 6M, which can be due to reciprocal translocation. Subspecies also differ in the amount and distribution of microsatellite and satellite DNA sequences, the number and position of minor NORs, especially on 3M and 6M, and gliadin spectra mainly in the a-zone. Frequent occurrence of hybrids can be caused by open pollination, which, along with genetic heterogeneity of accessions and, probably, the lack of geographic or genetic barrier between the subspecies, may contribute to extremely broad intraspecific variation of GAAn and gliadin patterns in Ae. comosa, which are usually not observed in endemic plant species.

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DOI: 10.3897/compcytogen.17.100945

Authors: Ananda Ribeiro Macedo de Andrade, Danon Clemes Cardoso, Maykon Passos Cristiano

Abstract: The family Formicidae is composed of ants that organize themselves into castes in which every individual has a joint organizational function. Solenopsis Westwood, 1840 is an ant genus with opportunistic and aggressive characteristics, known for being invasive species and stings that cause burning in humans. This genus is particularly difficult to classify and identify since its morphology provides few indications for species differentiation. For this, a tool that has been useful for evolutionary and taxonomic studies is cytogenetics. Here, we cytogenetically studied Solenopsis saevissima Smith, 1855 from Ouro Preto, Minas Gerais, Brazil. We evaluated the occurrence of polyploid cells in individuals and colonies by conventional cytogenetics. A total of 450 metaphases were analyzed and counted. Chromosome counts of individuals and colonies showed varied numbers of ploidies, from n = 16 to 8n = 128. The karyomorphometrical approach allowed determination of the following karyotypes: n = 10 m + 4 sm + 2 st, 2n = 20 m + 8 sm + 4 st, and 4n = 40 m + 16 sm + 8 st. Polyploidy can be found naturally in individuals and colonies and may represent an adaptative trait related to widespread distribution and invasion ability of new habitats.

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DOI: 10.3897/compcytogen.v17.i1.99236

Authors: Chao-Wen She, Xiang-Hui Jiang, Chun-Ping He

Abstract: To have an insight into the karyotype variation of eight Cucurbitaceae crops including Cucumis sativus Linnaeus, 1753, Cucumis melo Linnaeus, 1753, Citrullus lanatus (Thunberg, 1794) Matsumura et Nakai, 1916, Benincasa hispida (Thunberg, 1784) Cogniaux, 1881, Momordica charantia Linnaeus, 1753, Luffa cylindrica (Linnaeus, 1753) Roemer, 1846, Lagenaria siceraria var. hispida (Thunberg, 1783) Hara, 1948 and Cucurbita moschata Duchesne ex Poiret, 1819, well morphologically differentiated mitotic metaphase chromosomes were prepared using the enzymatic maceration and flame-drying method, and the chromosomal distribution of heterochromatin and 18S-5.8S-26S rRNA genes (45S rDNA) was investigated using sequential combined PI and DAPI (CPD) staining and fluorescence in situ hybridization (FISH) with 45S rDNA probe. Detailed karyotypes were established using the dataset of chromosome measurements, fluorochrome bands and rDNA FISH signals. Four karyotype asymmetry indices, CVCI, CVCL, MCA and Stebbins’ category, were measured to elucidate the karyological relationships among species. All the species studied had symmetrical karyotypes composed of metacentric and submetacentric or only metacentric chromosomes, but their karyotype structure can be discriminated by the scatter plot of MCA vs. CVCL. The karyological relationships among these species revealed by PCoA based on x, 2n, TCL, MCA, CVCL and CVCI was basically in agreement with the phylogenetic relationships revealed by DNA sequences. CPD staining revealed all 45S rDNA sites in all species, (peri)centromeric GC-rich heterochromatin in C. sativus, C. melo, C. lanatus, M. charantia and L. cylindrica, terminal GC-rich heterochromatin in C. sativus. DAPI counterstaining after FISH revealed pericentromeric DAPI+ heterochromatin in C. moschata. rDNA FISH detected two 45S loci in five species and five 45S loci in three species. Among these 45S loci, most were located at the terminals of chromosome arms, and a few in the proximal regions. In C. sativus, individual chromosomes can be precisely distinguished by the CPD band and 45S rDNA signal patterns, providing an easy method for chromosome identification of cucumber. The genome differentiation among these species was discussed in terms of genome size, heterochromatin, 45S rDNA site, and karyotype asymmetry based on the data of this study and previous reports.

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DOI: 10.3897/compcytogen.v7.i1.97165

Authors: Eugene Yu. Krysanov, Béla Nagy, Brian R. Watters, Alexandr Sember, Sergey A. Simanovsky

Abstract: The karyotype differentiation of the twelve known members of the Nothobranchius ugandensis Wildekamp, 1994 species group is reviewed and the karyotype composition of seven of its species is described herein for the first time using a conventional cytogenetic protocol. Changes in the architecture of eukaryotic genomes often have a major impact on processes underlying reproductive isolation, adaptation and diversification. African annual killifishes of the genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), which are adapted to an extreme environment of ephemeral wetland pools in African savannahs, feature extensive karyotype evolution in small, isolated populations and thus are suitable models for studying the interplay between karyotype change and species evolution. The present investigation reveals a highly conserved diploid chromosome number (2n = 36) but a variable number of chromosomal arms (46–64) among members of the N. ugandensis species group, implying a significant role of pericentric inversions and/or other types of centromeric shift in the karyotype evolution of the group. When superimposed onto a phylogenetic tree based on molecular analyses of two mitochondrial genes the cytogenetic characteristics did not show any correlation with the phylogenetic relationships within the lineage. While karyotypes of many other Nothobranchius spp. studied to date diversified mainly via chromosome fusions and fissions, the N. ugandensis species group maintains stable 2n and the karyotype differentiation seems to be constrained to intrachromosomal rearrangements. Possible reasons for this difference in the trajectory of karyotype differentiation are discussed. While genetic drift seems to be a major factor in the fixation of chromosome rearrangements in Nothobranchius, future studies are needed to assess the impact of predicted multiple inversions on the genome evolution and species diversification within the N. ugandensis species group.

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DOI: 10.3897/compcytogen.v17.i1.94943

Authors: Denis V. Prazdnikov

Abstract: Snakehead fishes of the family Channidae are obligatory air-breathers freshwater predators, the vast majority of which belong to the genus Channa Scopoli, 1777. Channa species are characterized by high karyotypic diversity due to various types of chromosomal rearrangements. It is assumed that, in addition to the lifestyle, fragmentation and isolation of snakehead populations contribute to an increase in karyotypic diversity. However, the chromosome complements of many isolated populations of widespread Channa species remain unknown, and the direction of karyotype transformations is poorly understood. This paper describes the previously unstudied karyotypes of Channa lucius (Cuvier, 1831) and C. striata (Bloch, 1793) from Phu Quoc Island and analyzes the trends of karyotypic evolution in the genus Channa. In C. lucius, the karyotypes are differed in the number of chromosome arms (2n = 48, NF = 50 and 51), while in C. striata, the karyotypes are differed in the diploid chromosome number (2n = 44 and 43, NF = 48). A comparative cytogenetic analysis showed that the main trend of karyotypic evolution of Channa species is associated with a decrease in the number of chromosomes and an increase in the number of chromosome arms, mainly due to fusions and pericentric inversions. The data obtained support the assumption that fragmentation and isolation of populations, especially of continental islands, contribute to the karyotypic diversification of snakeheads and are of interest for further cytogenetic studies of Channidae.

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DOI: 10.3897/compcytogen.v16.i4.95659

Authors: Veronika V. Golygina

Abstract: Species Chironomus sp. prope agilis Kiknadze, Siirin, Filippova et al., 1991 belongs to the Ch. plumosus group of sibling species. It was described on the basis of its karyotype and analysis of isozymes from one population in the Urals but since then no quantitative data on chromosomal polymorphism of this species have been published. The goal of this study is to broaden our knowledge of the chromosomal polymorphism and distribution of the Chironomus sp. prope agilis, which, along with the data on chromosomal polymorphism of other species from the Ch. plumosus group, can give us a better understanding of the connection between chromosomal polymorphism and ecological conditions of habitats. The specimens of Chironomus sp. prope agilis were found only in 8 natural populations from the Urals, Western Siberia and Kazakhstan, which allows us to conclude that the species range of Chironomus sp. prope agilis is not as wide as for most other species from Ch. plumosus group. An analysis of chromosomal polymorphism in these 8 natural populations of Chironomus sp. prope agilis has been performed. All of the studied populations were either monomorphic or showed very low level of chromosomal polymorphism, with 4.4–8.7% of heterozygous specimens per population and 0.04–0.08 heterozygotic inversion per larvae. The total number of banding sequences found in the banding sequence pool of Chironomus sp. prope agilis is 10. The mapping of banding sequence p’ag2B3 is presented for the first time. Besides inversions, one reciprocal translocation was found in a population from Kazakhstan, B-chromosome was found in one population from the Urals region of Russia, and heterozygosity of the level of expression of Balbiany rings in arm G was observed in several studied populations.

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DOI: 10.3897/CompCytogen.v16.i4.90558

Authors: Laurian Parmentier, Roger Vila, Vladimir Lukhtanov

Abstract: The Balkan Peninsula is one of the greatest hotspots for biodiversity in Europe. While the region has been investigated thoroughly, some parts remain understudied and may still harbour undiscovered diversity, even in well-studied organisms such as Lepidoptera. Here we investigated the group of the so-called anomalous blue butterflies, also known as ‘brown complex’ of the subgenus Agrodiaetus Hübner, 1822 including the taxa of the entire Polyommatus aroaniensis (Brown, 1976) species complex. This species complex is distributed in the southern part of the Balkan Peninsula and known to be represented by three closely related allopatric species, differentiated by their chromosome numbers (n) and mitochondrial (mt) DNA. These are P. aroaniensis sensu stricto (Southern Greece, Peloponnese, n=47–48; mt haplogroup aroa1), P. timfristos Lukhtanov, Vishnevskaya et Shapoval, 2016 (Central Greece, Attika, n=38, aroa2) and P. orphicus Kolev, 2005 (North-Eastern Greece, Southern Bulgaria, n=41–42, orph1). Based on an analysis of chromosomal, molecular and morphological markers, we demonstrate that a fourth taxon of this species complex exists in Albania. This taxon possesses the mt haplogroup aroa3, which is the most differentiated within the entire P. aroaniensis species complex, and the karyotype (n=42–43), which differs by one fixed chromosome fission from P. orphicus. The Albanian taxon seems to be ecologically specialised (habitat on dark-coloured, ophiolitic substrate soils) and differs in colouration (wing reflectance) from the others taxa of the P. aroaniensis species group. Based on the evidence here presented and following the current view of the taxonomy of the group, we propose considering the Albanian taxon as a new species, here described as Polyommatus lurae sp. nov. At the contact zone between the new species and P. orphicus, in addition to typical ones, we detected specimens with haplogroup orph2, karyotype n=43 and intermediate morphology, which seem to represent P. lurae × P. orphicus hybrids.

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DOI: 10.3897/CompCytogen.v16i4.85059

Authors: Jiří Král, Ivalú M. Ávila Herrera, František Šťáhlavský, David Sadílek, Jaroslav Pavelka, Maria Chatzaki, Bernhard A. Huber

Abstract: Haplogyne araneomorphs are a diverse spider clade. Their karyotypes are usually predominated by biarmed (i.e., metacentric and submetacentric) chromosomes and have a specific sex chromosome system, X1X2Y. These features are probably ancestral for haplogynes. Nucleolus organizer regions (NORs) spread frequently from autosomes to sex chromosomes in these spiders. This study focuses on pholcids (Pholcidae), a highly diverse haplogyne family. Despite considerable recent progress in pholcid cytogenetics, knowledge on many clades remains insufficient including the most species-rich pholcid genus, Pholcus Walckenaer, 1805. To characterize the karyotype differentiation of Pholcus in Europe, we compared karyotypes, sex chromosomes, NORs, and male meiosis of seven species [P. alticeps Spassky, 1932; P. creticus Senglet, 1971; P. dentatus Wunderlich, 1995; P. fuerteventurensis Wunderlich, 1992; P. phalangioides (Fuesslin, 1775); P. opilionoides (Schrank, 1781); P. silvai Wunderlich, 1995] representing the dominant species groups in this region. The species studied show several features ancestral for Pholcus, namely the 2n♂ = 25, the X1X2Y system, and a karyotype predominated by biarmed chromosomes. Most taxa have a large acrocentric NOR-bearing pair, which evolved from a biarmed pair by a pericentric inversion. In some lineages, the acrocentric pair reverted to biarmed. Closely related species often differ in the morphology of some chromosome pairs, probably resulting from pericentric inversions and/or translocations. Such rearrangements have been implicated in the formation of reproductive barriers. While the X1 and Y chromosomes retain their ancestral metacentric morphology, the X2 chromosome shows a derived (acrocentric or subtelocentric) morphology. Pairing of this element is usually modified during male meiosis. NOR patterns are very diverse. The ancestral karyotype of Pholcus contained five or six terminal NORs including three X chromosome-linked loci. The number of NORs has been frequently reduced during evolution. In the Macaronesian clade, there is only a single NOR-bearing pair. Sex chromosome-linked NORs are lost in Madeiran species and in P. creticus. Our study revealed two cytotypes in the synanthropic species P. phalangioides (Madeiran and Czech), which differ by their NOR pattern and chromosome morphology. In the Czech cytotype, the large acrocentric pair was transformed into a biarmed pair by pericentric inversion.

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DOI: 10.3897/CompCytogen.v16i3.89911

Authors: Marija Rajičić, Ivana Budinski, Milan Miljević, Branka Bajić, Milan Paunović, Mladen Vujošević, Jelena Blagojević

Abstract: B chromosomes (Bs) are supernumerary to the standard chromosome set, from which they prevalently derive. Variation in numbers both among individuals or populations and among cells within individuals is their constant feature. Leisler’s bat Nyctalus leisleri (Kuhl, 1817) is one of only four species of Chiroptera with detected Bs. Four males of N. leisleri were collected from two localities on the territory of Serbia and cytogenetically analysed. All animals had Bs with interindividual variability ranging from two to five heterochromatic micro Bs. The highest number of Bs was detected in this species. Among mammals, Rodentia and Chiroptera are orders with the largest number of species, but Bs frequently appear in rodents and rarely in chiropterans. Possible explanations for this difference are offered.

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DOI: 10.3897/compcytogen.v16.i3.90336

Authors: Viktor V. Bolshakov, Ekaterina A. Movergoz

Abstract: Karyotype and COI gene sequences of Chironomus melanotus Keyl, 1961 from the Yaroslavl region (Russia) were analyzed. A low level of chromosomal polymorphism has been confirmed, eventually eight banding sequences were found: melA1, melB1, melC1, melD1, melE1, melF1, and melG1; only melD2 was found in two larvae from the Sunoga river. Analysis of phylogenetic tree and estimated genetic distances has shown not all COI gene sequences of Ch. melanotus in GenBank and BOLD to belong to this species. The lower distance of 0.4% was observed between two sequences from the Yaroslavl region and Finland, apparently these are true Ch. melanotus sequences. The distances between true Ch. melanotus and other sequences from Finland were 9.5% and 12.4%, and from Sweden it was 11%. The average genetic distance between studied sequences of 9.1% is out of the range of the 3% threshold previously determined for chironomids. According to our estimates, there are two sequences with a distance of 2.9% that may belong to Ch. annularius Meigen, 1818, and one sequence with a genetic distance of 2.1%, may belonging to Ch. cingulatus Meigen, 1830, which has been confirmed karyologically. Another two sequences form a separate cluster. We suggest that they either belong to a known species, but are not present in the databases, or belong to a distinct, undescribed species.

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DOI: 10.3897/compcytogen.v16.i3.82641

Authors: Ramon Costa Dominato, Guilherme Costa de Oliveira, Carla Santana Cassini, Victor Goyannes Dill Orrico, Cléa dos Santos Ferreira Mariano, Janisete Gomes Silva

Abstract: The genus Adenomera Steindachner, 1867 currently comprises 29 nominal species, some of which are suggested to be cryptic species complexes. The present study was carried out with specimens of the “thomei” clade that encompasses three taxa distributed in the Atlantic Forest biome: Adenomera thomei Almeida et Angulo, 2006, Adenomera sp. L., and Adenomera sp. M. We used classical cytogenetics to describe the diploid number and karyomorphology of these three species collected in two different locations in the state of Bahia, Brazil. Our results revealed the diploid number 2n = 24 (FN = 34) with two pairs of metacentric chromosomes (pairs 1 and 5), three pairs of submetacentric chromosomes (pairs 2, 3, and 4), and seven pairs of telocentric chromosomes (pairs 6, 7, 8, 9, 10, 11, and 12). Further morphological, bioacoustic, and cytogenetic data (C-banding and AgNor) are needed to better delineate the lineages within the “thomei” clade.

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DOI: 10.3897/compcytogen.v16.i2.79133

Authors: Sergey A. Simanovsky, Dmitry A. Medvedev, Fekadu Tefera, Alexander S. Golubtsov

Abstract: The Afrotropical lutefish family Citharinidae (Citharinoidei, Characiformes) comprises three genera with eight species in total. Although Citharinidae have been studied in terms of taxonomy and systematics, no cytogenetic information was available for any representative of the family. Furthermore, only one species out of 116 in Citharinoidei (Distichodus affinis Günther, 1873) has been studied cytogenetically. Here, we report the karyotypes of Citharinus citharus (Geoffroy St. Hilaire, 1809) from West Africa and Citharinus latus Müller et Troschel, 1844 from Northeast Africa. The former has the diploid chromosome number 2n = 40 and the fundamental number FN = 80, while the latter has 2n = 44 and FN = 88. Hence, these karyotypes consist exclusively of bi-armed chromosomes. Such karyotypes were previously found in D. affinis and in many lineages of Neotropical species of another suborder of Characiformes, Characoidei. In contrast, the karyotypes dominated by uni-armed elements are typical for a number of phylogenetically basal lineages of Afrotropical and Neotropical Characoidei. We discuss the importance of our data on Citharinidae for the understanding of the karyotype evolution within the order Characiformes.

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DOI: 10.3897/CompCytogen.v16i2.72190

Authors: Cristian Andrés Araya-Jaime, Duílio Mazzoni Zerbinato de Andrade Silva, Luís Ricardo Ribeiro da Silva, Cristiano Neves do Nascimento, Claudio Oliveira, Fausto Foresti

Abstract: The genus Eigenmannia Jordan et Evermann,1896 includes electric fishes endemic to the Neotropical region with extensive karyotype variability and occurrence of different sex chromosome systems, however, cytogenetic studies within this group are restricted to few species. Here, we describe the karyotypes of Eigenmannia limbata (Schreiner et Miranda Ribeiro, 1903) and E. microstoma (Reinhardt, 1852) and the chromosomal locations of 5S and 18S rDNAs (ribosomal RNA genes) and U2 snDNA (small nuclear RNA gene). Among them, 18S rDNA sites were situated in only one chromosomal pair in both species, and co-localized with 5S rDNA in E. microstoma. On the other hand, 5S rDNA and U2 snRNA sites were observed on several chromosomes, with variation in the number of sites between species under study. These two repetitive DNAs were observed co-localized in one chromosomal pair in E. limbata and in four pairs in E. microstoma. Our study shows a new case of association of these two types of repetitive DNA in the genome of Gymnotiformes.

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DOI: 10.3897/compcytogen.v16.i2.79033

Authors: Biplab Kumar Bhowmick, Sumita Jha

Abstract: The cytogenetic relationships in the species of Cucurbitaceae are becoming immensely important to answer questions pertaining to genome evolution. Here, a simplified and updated data resource on cytogenetics of Cucurbitaceae is presented on the basis of foundational parameters (basic, zygotic and gametic chromosome numbers, ploidy, genome size, karyotype) and molecular cytogenetics. We have revised and collated our own findings on seven agriculturally important Indian cucurbit species in a comparative account with the globally published reports. Chromosome count (of around 19% species) shows nearly three-fold differences while genome size (of nearly 5% species) shows 5.84-fold differences across the species. There is no significant correlation between chromosome numbers and nuclear genome sizes. The possible trend of evolution is discussed here based on molecular cytogenetics data, especially the types and distribution of nucleolus organizer regions (NORs). The review supersedes the scopes of general chromosome databases and invites scopes for continuous updates. The offline resource serves as an exclusive toolkit for research and breeding communities across the globe and also opens scope for future establishment of web-database on Cucurbitaceae cytogenetics.

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DOI: 10.3897/compcytogen.v16.i1.78852

Authors: Naila Chahinez Boukhebache, Nabila Amirouche, Rachid Amirouche

Abstract: This paper provides new cytotaxonomic data on the genus Narcissus Linnaeus, 1753, in Algeria. Populations of seven taxa, N. tazetta Linnaeus, 1753, N. pachybolbus Durieu, 1847, N. papyraceus Ker Gawler, 1806, N. elegans (Haworth) Spach, 1846, N. serotinus sensu lato Linnaeus, 1753, including N. obsoletus (Haworth) Steudel, 1841, and N. cantabricus De Candolle, 1815, were karyologically investigated through chromosome counting and karyotype parameters. N. tazetta and N. elegans have the same number of chromosomes 2n = 2x = 20 with different karyotype formulas. Karyological and morphological characteristics, confirm the specific status of N. pachybolbus and N. papyraceus, both are diploids with 2n = 22 but differing in asymmetry indices. The morphotypes corresponding to N. serotinus sensu lato show two ploidy levels 2n = 4x = 20 and 2n = 6x = 30 characterized by a yellow corona. Some hexaploid cytotypes have more asymmetric karyotype with predominance of subtelocentric chromosomes. They are distinguished by orange corona and may correspond to N. obsoletus. Other cytotype 2n = 28 of N. serotinus was observed in the North Western biogeographic sectors. N. cantabricus was found to be diploid with 2n = 2x = 14, which is a new diploid report in the southernmost geographic range of this polyploid complex.

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DOI: 10.3897/compcytogen.v16.i1.79953

Authors: Rei Kawakami, Takahiro Taguchi, Joshua Vacarizas, Masumi Ito, Takuma Mezaki, Akira Tominaga, Satoshi Kubota

Abstract: We performed conventional and molecular cytogenetic studies on the Favites pentagona Esper, 1795, a scleractinian coral mostly found along the west coast of Japan. Karyotype analysis of F. pentagona by G-banding revealed a karyogram containing a homogenously staining region (HSR) on chromosome 10 in more than 50% of the examined metaphase spreads. This HSR consisted of sequences from 18S ribosomal RNA (rRNA) genes, as demonstrated by fluorescence in situ hybridization (FISH) and DNA sequencing. We highlighted the development of four chromosomal FISH markers from repetitive genes such as U2 small nuclear RNA linked to 5S rRNA sequence (U2 snRNA-5S), 18S rRNA, histone H3, and uncharacterized gene FP-9X. The chromosomal locations of the U2 snRNA-5S and 18S RNA were on the terminal end of long arm of chromosomes 2 and 10, respectively, while the histone H3 and the uncharacterized gene were located near the centromeres of chromosomes 1 and 9, respectively. These FISH markers will improve the karyotyping of F. pentagona from mitotic preparations which helps in widening our understanding of coral genetic structure and chromosome organization. In addition, these improvements in karyotyping will provide the basis in constructing of chromosome-level genome assembly for F. pentagona.

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DOI: 10.3897/compcytogen.v16.i1.79056

Authors: Helal Ahmad Ansari, Nicholas Ellison, Alan Vincent Stewart, Warren Mervyn Williams

Abstract: The Schedonorus-Lolium complex of the subtribe Loliinae (Poaceae) includes several economically important forage and turf grasses. This complex encompasses Lolium Linnaeus, 1753, Festuca Linnaeus, 1753 subgenus Schedonorus (P. Beauvois, 1824) Petermann, 1849 and Micropyropsis Romero Zarco et Cabezudo, 1983. New FISH results of 5S and 18S–26S rDNA sequences are presented for three species and the results are interpreted in a review of distribution patterns of 5S and 18S–26S rDNA sequences among other species in the complex. Micropyropsis tuberosa Romero Zarco et Cabezudo, 1983 (2n = 2x = 14) displayed a distribution pattern of rDNA sequences identical to that of F. pratensis Hudson, 1762, supporting a close phylogenetic relationship at the bottom of the phylogenetic tree. “Lolium multiflorum” Lamarck, 1779 accessions sourced from Morocco showed a different pattern from European L. multiflorum and could be a unique and previously uncharacterised taxon. North African Festuca simensis Hochstetter ex A. Richard, 1851 had a marker pattern consistent with allotetraploidy and uniparental loss of one 18S–26S rDNA locus. This allotetraploid has previously been suggested to have originated from a hybrid with Festuca glaucescens (Festuca arundinacea var. glaucescens Boissier, 1844). However, the distribution patterns of the two rDNA sequences in this allotetraploid do not align with F. glaucescens, suggesting that its origin from this species is unlikely. Furthermore, comparisons with other higher alloploids in the complex indicate that F. simensis was a potential donor of two sub-genomes of allohexaploid Festuca gigantea (Linnaeus) Villars, 1787. In the overall complex, the proximal locations of both rDNA markers were conserved among the diploid species. Two types of synteny of the two markers could, to a considerable extent, distinguish allo- and autogamous Lolium species. The ancestral parentage of the three Festuca allotetraploids has not yet been determined, but all three appear to have been sub-genome donors to the higher allopolypoids of sub-genus Schedonorus. Terminal locations of both the markers were absent from the diploids but were very frequently observed in the polyploids.

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DOI: 10.3897/CompCytogen.v16.i1.79182

Authors: Mukhamed Kh. Karmokov

Abstract: The study presents data on the karyotype characteristics and the mitochondrial gene COI sequences of the non-biting midge Chironomus bonus Shilova et sDzhvarsheishvili 1974 (Diptera Chironomidae) from the South Caucasus. The species belongs to the Ch. plumosus group of sibling species one of the most widespread and successful groups in the genus Chironomus Meigen 1803. The karyotype of the studied population is monomorphic. The morphological and chromosomal characteristics of Ch. bonus from the Caucasus are similar to those previously described for this species (Kiknadze et al. 1991a). In the phylogenetic tree based on the COI gene sequences one can observe several clear clusters. We named them Palearctic Ch. plumosus Far Eastern Ch. borokensis-Ch. suwai and Nearctic Ch. entis-Ch. plumosus clusters. The calculated K2P genetic distances within each cluster have not exceeded the 3% threshold for the genus Chironomus. Contrary to this the distances between the clusters exceed this range and correspond to separate species. The Ch. bonus sequences belong to the cluster consisting of Ch. plumosus (Linnaeus 1758) sequences from European populations and do not form a separate clade of the phylogenetic tree. One can suppose that the origin of the Ch. plumosus group of sibling species dates back to 5.75–3.43 million years ago (Mya) the epochs of Late Miocene (7,3–5,3 Mya) and early Pliocene (5,3–2,58 Mya). On the other hand Palearctic Ch. plumosus Far Eastern Ch. borokensis-Ch. suwai and Nearctic Ch. entis-Ch. plumosus clusters appeared relatively recently in the Middle Pleistocene 1.288–0.307 Mya. The possible relationship between the climate changes in the Pliocene and the origin of the Ch. plumosus group are discussed. Chironomidae

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DOI: 10.3897/compcytogen.v16.i1.76260

Authors: Marcello Mezzasalma, Franco Andreone, Gaetano Odierna, Fabio Maria Guarino, Angelica Crottini

Abstract: We performed a molecular and cytogenetic analysis on different Mantellinae species and revised the available chromosomal data on this group to provide an updated assessment of its karyological diversity and evolution. Using a fragment of the mitochondrial 16S rRNA, we performed a molecular taxonomic identification of the samples that were used for cytogenetic analyses. A comparative cytogenetic analysis, with Giemsa’s staining, Ag-NOR staining and sequential C-banding + Giemsa + CMA + DAPI was performed on eight species: Gephyromantis sp. Ca19, G. striatus (Vences, Glaw, Andreone, Jesu et Schimmenti, 2002), Mantidactylus (Chonomantis) sp. Ca11, M. (Brygoomantis) alutus (Peracca, 1893), M. (Hylobatrachus) cowanii (Boulenger, 1882), Spinomantis prope aglavei “North” (Methuen et Hewitt, 1913), S. phantasticus (Glaw et Vences, 1997) and S. sp. Ca3. Gephyromantis striatus, M. (Brygoomantis) alutus and Spinomantis prope aglavei “North” have a karyotype of 2n = 24 chromosomes while the other species show 2n = 26 chromosomes. Among the analysed species we detected differences in the number and position of telocentric elements, location of NOR loci (alternatively on the 6th, 7th or 10th pair) and in the distribution of heterochromatin, which shows species-specific patterns. Merging our data with those previously available, we propose a karyotype of 2n = 26 with all biarmed elements and loci of NORs on the 6th chromosome pair as the ancestral state in the whole family Mantellidae. From this putative ancestral condition, a reduction of chromosome number through similar tandem fusions (from 2n = 26 to 2n = 24) occurred independently in Mantidactylus Boulenger, 1895 (subgenus Brygoomantis Dubois, 1992), Spinomantis Dubois, 1992 and Gephyromantis Methuen, 1920. Similarly, a relocation of NORs, from the putative primitive configuration on the 6th chromosome, occurred independently in Gephyromantis, Blommersia Dubois, 1992, Guibemantis Dubois, 1992, Mantella Boulenger, 1882 and Spinomantis. Chromosome inversions of primitive biarmed elements likely generated a variable number of telocentric elements in Mantella nigricans Guibé, 1978 and a different number of taxa of Gephyromantis (subgenera Duboimantis Glaw et Vences, 2006 and Laurentomantis Dubois, 1980) and Mantidactylus (subgenera Brygoomantis, Chonomantis Glaw et Vences, 1994, Hylobatrachus Laurent, 1943 and Ochthomantis Glaw et Vences, 1994).

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DOI: 10.3897/compcytogen.v15.i4.75990

Authors: Alessio Turco, Antonella Albano, Pietro Medagli, Robert P. Wagensommer, Saverio D'Emerico

Abstract: In our study, FISH mapping using 18S-5.8S-25S rDNA and 5S rDNA sequences was performed for the first time on Ophrys tenthredinifera Willdenow, 1805, Serapias vomeracea (Burman f., 1770) Briquet, 1910 and Himantoglossum hircinum (Linnaeus, 1753) Sprengel, 1826. A detailed study was also performed on O. tenthredinifera using Giemsa-staining, silver-staining, CMA fluorescence banding and fluorescence in situ hybridisation (FISH) with rDNA probes. We analysed two subspecies, i.e. O. tenthredinifera subsp. neglecta (Parlatore, 1860) E.G. Camus, 1908 and O. tenthredinifera subsp. grandiflora (Tenore, 1819) Kreutz, 2004 by the traditional Feulgen method and constructed the karyotype. The cytotaxonomic implications for both taxa are also discussed. In Himantoglossum hircinum, FISH and silver staining highlighted differences in the number of two rDNA families (35S and 5S) with respect to Barlia robertiana (Loiseleur-Deslongchamps, 1807) Greuter, 1967. In addition, fluorescence in situ hybridisation was also applied to diploid (2n = 2x = 36) and triploid (2n = 3x = 54) Anacamptis morio (Linnaeus, 1753) R.M. Bateman, Pridgeon et M.W. Chase, 1997. As far as we are aware, this is the first case of autotriploidy observed in A. morio.

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DOI: 10.3897/CompCytogen.v15.i4.76761

Authors: Veronika V. Golygina, Oksana V. Ermolaeva

Abstract: Quantitative and qualitative analysis of chromosomal polymorphism in 19 natural populations of Ch. agilis had been performed. Most studied populations showed a medium level of chromosomal polymorphism: on average 45±3.0% of specimens are heterozygotes with 0.52±0.01 heterozygotic inversion per larvae. Besides inversions, B-chromosomes were found in two populations. The total number of banding sequences found in banding sequence pool of Ch. agilis is 16. Three banding sequences – p’agiB3, p’agiD3, p’agiF3 – are described for the first time.

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DOI: 10.3897/CompCytogen.v15.i4.78718

Authors: Dmitry A. Gapon, Valentina G. Kuznetsova, Anna Maryańska-Nadachowska

Abstract: A new species, Rhaphidosoma paganicum sp. nov. (Heteroptera: Reduviidae: Harpactorinae: Rhaphidosomatini), is described from the Dry Zone of Myanmar. It is the fifth species of Rhaphidosoma Amyot et Serville, 1843, known from the Oriental Region, and the first record of the genus for Myanmar and Indochina. The structure of the external and internal terminalia of the male and female is described and illustrated in detail. The completely inflated endosoma is described for the first time in reduviids. The complex structure of the ductus seminis is shown; it terminates with a voluminous seminal chamber which opens with a wide secondary gonopore and may be a place where spermatophores are formed. The new species is compared with all congeners from the Oriental Region and Western Asia. It is characterised by the absence of distinct tubercles on the abdominal tergites of the male, the presence only two long tubercles and small rounded ones on the abdominal tergites VII and VI, respectively, in the female, the presence of short fore wing vestiges which are completely hidden under longer fore wing vestiges, and other characters. In addition to the morphological description, an account is given of the male karyotype and the structure of testes of Rh. paganicum sp. nov. and another species of Harpactorinae, Polididus armatissimus Stål, 1859 (tribe Harpactorini). It was found that Rh. paganicum sp. nov. has a karyotype comprising 12 pairs of autosomes and a multiple sex chromosome system (2n♂=24A+X1X2X3Y), whereas P. armatissimus has a karyotype comprising five pairs of autosomes and a simple sex chromosome system (2n♂=10A+XY). The males of these species were found to have seven and nine follicles per testis, respectively. FISH mapping of 18S ribosomal DNA (major rDNA) revealed hybridisation signals on two of the four sex chromosomes (Y and one of the Xs) in Rh. paganicum sp. nov. and on the largest pair of autosomes in P. armatissimus. The presence of the canonical “insect” (TTAGG)n telomeric repeat was detected in the chromosomes of both species. This is the first application of FISH in the tribe Raphidosomatini and in the genus Polididus Stål, 1858.

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DOI: 10.3897/CompCytogen.v15.i4.71295

Authors: Vemula Harshini, P. Kumarasamy, S.M.K. Karthickeyan

Abstract: A chromosomal polymorphism was detected on karyological screening of Kangayam breeding sires prior to subjecting them for frozen semen collection. One bull possessed the chromosomal complement 2n = 60, consisting of 58 acrocentric autosomes, one large sub-metacentric X-chromosome, and one small acrocentric Y-chromosome with a small visible p-arm, which was further confirmed using CBG- and GTG-banding. This polymorphism was attributed to a heterochromatin variation of the acrocentric Y-chromosome routine in the Bos indicus Linnaeus, 1758 cattle.

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DOI: 10.3897/CompCytogen.v15i4.73135

Authors: Viktor V. Bolshakov, Alexander A. Prokin, Sergey V. Artemenko

Abstract: The karyotype features and gene COI sequence of Chironomus heteropilicornis Wülker, 1996 from the Gydan Peninsula are presented for the first time. Nine banding sequences were determined, eight of them hpiA2, hpiB1, hpiC1, hpiC2, hpiD1, hpiE1, hpiF3 and hpiG1 were previously known from European, Georgian (South Caucasus) and Siberian populations. One new banding sequence for Ch. heteropilicornis, hpiB2, was found. The hpiA2 banding sequence was found in all individuals, and this is its second finding after the Georgian population (Karmokov 2019). The hpiF3 banding sequence was found only in the homozygous state. Additional B-chromosomes are absent. The genetic distances (K2P) between Ch. heteropilicornis COI gene sequence from Gydan Peninsula and Norway are 1.1­–1.3%, and Georgia – 1.8%, much lower than the commonly accepted threshold of 3% for species of genus Chironomus Meigen, 1803. The phylogenetic tree for COI gene sequences estimated by Bayesian inference showed geographically determined clusters of Norway and Gydan and a separate lineage of the Georgian population of Ch. heteropilicornis. The analysis of karyotype and COI gene sequences shows that the population of Ch. heteropilicornis from the Gydan Peninsula has an intermediate position within the Ch. pilicornis group between Georgian, Yakutian and Norwegian populations. The position of Ch. pilicornis Fabricius, 1787 from Canada and Greenland on the phylogenetic tree is discussed.

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DOI: 10.3897/CompCytogen.v15.i4.69638

Authors: Rodrigo Xavier Soares, Clóvis Coutinho da Motta-Neto, Gideão Wagner Werneck Félix da Costa, Marcelo de Bello Cioffi, Luiz Antonio Carlos Bertollo, Amanda Torres Borges, Wagner Franco Molina

Abstract: Carangidae are an important and widespreaded family of pelagic predatory fishes that inhabit reef regions or open ocean areas, some species occupying a vast circumglobal distribution. Cytogenetic comparisons among representatives of its different tribes help to understand the process of karyotype divergence in marine ecosystems due to the variable migratory ability of species. In this sense, conventional cytogenetic investigations (Giemsa staining, Ag-NORs, and C-banding), GC base-specific fluorochrome staining and FISH mapping of ribosomal DNAs were performed. Four species, Elagatis bipinnulata (Quoy et Gaimard, 1825) and Seriola rivoliana (Valenciennes, 1883) (Naucratini), with circumtropical distributions, Gnathanodon speciosus (Forsskål, 1775) (Carangini), widely distributed in the tropical and subtropical waters of the Indian and Pacific oceans, and Trachinotus carolinus (Linnaeus, 1766) (Trachinotini), distributed along the western Atlantic Ocean, were analyzed, thus encompassing representatives of three out its four tribes. All species have diploid chromosome number 2n = 48, with karyotypes composed mainly by acrocentric chromosomes (NF = 50–56). The 18S rDNA/Ag-NORs/GC+ and 5S rDNA loci were located on chromosomes likely homeologs. Karyotypes showed a pattern considered basal for the family or with small variations in their structures, apparently due to pericentric inversions. The migratory capacity of large pelagic swimmers, in large distribution areas, likely restricts the fixation of chromosome changes in Carangidae responsible for a low level of karyotype diversification.

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DOI: 10.3897/compcytogen.v15.i4.73769

Authors: Gisele Amaro Teixeira, Luísa Antônia Campos Barros, Hilton Jeferson Alves Cardoso de Aguiar, Denilce Meneses Lopes

Abstract: Cytogenetic studies on fungus-farming ants have shown remarkable karyotype diversity, suggesting different chromosomal rearrangements involved in karyotype evolution in some genera. A notable cytogenetic characteristic in this ant group is the presence of GC-rich heterochromatin in the karyotypes of some ancient and derivative species. It was hypothesized that this GC-rich heterochromatin may have a common origin in fungus-farming ants, and the increase in species studied is important for understanding this question. In addition, many genera within the subtribe Attina have few or no cytogenetically studied species; therefore, the processes that shaped their chromosomal evolution remain obscure. Thus, in this study, we karyotyped, through classical and molecular cytogenetic techniques, the fungus-farming ants Cyphomyrmex transversus Emery, 1894, Sericomyrmex maravalhas Ješovnik et Schultz, 2017, and Mycetomoellerius relictus (Borgmeier, 1934), to provide insights into the chromosomal evolution in these genera and to investigate the presence the GC-rich heterochromatin in these species. Cyphomyrmex transversus (2n = 18, 10m + 2sm + 6a) and S. maravalhas (2n = 48, 28m + 20sm) showed karyotypes distinct from other species from their genera. Mycetomoellerius relictus (2n = 20, 20m) presented the same karyotype as the colonies previously studied. Notably, C. transversus presented the lowest chromosomal number for the genus and a distinct karyotype from the other two previously observed for this species, showing the existence of a possible species complex and the need for its taxonomic revision. Chromosomal banding data revealed GC-rich heterochromatin in all three species, which increased the number of genera with this characteristic, supporting the hypothesis of a common origin of GC-rich heterochromatin in Attina. Although a single chromosomal pair carries rDNA genes in all studied species, the positions of these rDNA clusters varied. The rDNA genes were located in the intrachromosomal region in C. transversus and M. relictus, and in the terminal region of S. maravalhas. The combination of our molecular cytogenetic data and observations from previous studies corroborates that a single rDNA site located in the intrachromosomal region is a plesiomorphic condition in Attina. In addition, cytogenetic data obtained suggest centric fission events in Sericomyrmex Mayr, 1865, and the occurrence of inversions as the origin of the location of the ribosomal genes in M. relictus and S. maravalhas. This study provides new insights into the chromosomal evolution of fungus-farming ants.

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DOI: 10.3897/compcytogen.v15.i4.67112

Authors: Irina V. Kartavtseva, Irina N. Sheremetyeva, Marina V. Pavlenko

Abstract: The vole Alexandromys evoronensis (Kovalskaya et Sokolov, 1980) with its two chromosomal races, “Evoron” (2n = 38–41, NF = 54–59) and “Argi” (2n = 34, 36, 37, NF = 51–56) is the endemic vole found in the Russian Far East. For the “Argi” chromosomal race, individuals from two isolated populations in mountain regions were investigated here for the first time using GTG-, GTC-, NOR methods. In the area under study, 8 new karyotype variants have been registered. The karyotype with 2n = 34 has a rare tandem fusion of three autosomes: two biarmed (Mev6 and Mev7) and one acrocentric (Mev14) to form a large biarmed chromosome (Mev6/7/14), all of which reveal a heterozygous state. For A. evoronensis, the variation in the number of chromosomes exceeded the known estimate of 2n = 34, 36 and amounted to 2n = 34, 36, 38–41. The combination of all the variations of chromosomes for the species made it possible to describe 20 variants of the A. evoronensis karyotype, with 11 chromosomes being involved in multiple structural rearrangements. In the “Evoron” chromosomal race 4 chromosomes (Mev1, Mev4, Mev17, and Mev18) and in the “Argi” chromosomal race 9 chromosomes (Mev6, Mev7, Mev14, Mev13, Mev11, Mev15, Mev17, Mev18, and Mev19) were observed. Tandem and Robertsonian rearrangements (Mev17/18 and Mev17.18) were revealed in both chromosomal races “Evoron” and “Argi”.

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DOI: 10.3897/compcytogen.v15.i4.71525

Authors: Xiaoyan Tao, Bo Liu, Quanwen Dou

Abstract: Kengyilia hirsuta (Keng, 1959) J. L. Yang, C. Yen et B. R. Baum, 1992, a perennial hexaploidy species, is a wild relative species to wheat with great potential for wheat improvement and domestication. The genome structure and cross-species homoeology of K. hirsuta chromosomes with wheat were assayed using 14 single-gene probes covering all seven homoeologous groups, and four repetitive sequence probes 45S rDNA, 5S rDNA, pAs1, and (AAG)10 by FISH. Each chromosome of K. hirsuta was well characterized by homoeological determination and repeats distribution patterns. The synteny of chromosomes was strongly conserved in the St genome, whereas synteny of the Y and P genomes was more distorted. The collinearity of 1Y, 2Y, 3Y and 7Y might be interrupted in the Y genome. A new 5S rDNA site on 2Y might be translocated from 1Y. The short arm of 3Y might involve translocated segments from 7Y. The 7 Y was identified as involving a pericentric inversion. A reciprocal translocation between 2P and 4P, and tentative structural aberrations in the subtelomeric region of 1PL and 4PL, were observed in the P genome. Chromosome polymorphisms, which were mostly characterized by repeats amplification and deletion, varied between chromosomes, genomes, and different populations. However, two translocations involving a P genome segmental in 3YL and a non-Robertsonial reciprocal translocation between 4Y and 3P were identified in two independent populations. Moreover, the proportion of heterozygous karyotypes reached almost 35% in all materials, and almost 80% in the specific population. These results provide new insights into the genome organization of K. hirsuta and will facilitate genome dissection and germplasm utilization of this species.

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DOI: 10.3897/CompCytogen.v15.i4.68761

Authors: Liliana M. Mola, María Florencia Fourastié, Silvia Susana Agopian

Abstract: The American dragonfly genus Orthemis Hagen, 1861 is mainly found in the Neotropical region. Seven of 28 taxonomically described species have been reported from Argentina. Chromosome studies performed on this genus showed a wide variation in chromosome number and a high frequency of the neoXY chromosomal sex-determination system, although the sexual pair was not observed in all cases. This work analyzes the spermatogenesis of Orthemis discolor (Burmeister, 1839), O. nodiplaga Karsch, 1891 and O. ambinigra Calvert, 1909 in individuals from the provinces of Misiones and Buenos Aires, Argentina. Orthemis discolor has 2n=23, n=11+X and one larger bivalent. Orthemis nodiplaga exhibits the largest chromosome number of the order, 2n=41, n=20+X and small chromosomes. Orthemis ambinigra shows a reduced complement, 2n=12, n=5+neo-XY, large-sized chromosomes, and a homomorphic sex bivalent. Fusions and fragmentations are the main evolutionary mechanisms in Odonata, as well as in other organisms with holokinetic chromosomes. Orthemis nodiplaga would have originated by nine autosomal fragmentations from the ancestral karyotype of the genus (2n=22A+X in males). We argue that the diploid number 23 in Orthemis has a secondary origin from the ancestral karyotype of family Libellulidae (2n=25). The complement of O. ambinigra would have arisen from five autosomal fusions and the insertion of the X chromosome into a fused autosome. C-banding and DAPI/CMA3 staining allowed the identification of the sexual bivalent, which revealed the presence of constitutive heterochromatin. We propose that the chromosome with intermediate C-staining intensity and three medial heterochromatic regions corresponds to the neo-Y and that the neo-system of this species has an ancient evolutionary origin. Moreover, we discuss on the mechanisms involved in the karyotypic evolution of this genus, the characteristics of the neo sex-determining systems and the patterns of heterochromatin distribution, quantity and base pair richness.

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DOI: 10.3897/compcytogen.v15.i4.67681

Authors: Sergey Simanovsky, Dmitry Medvedev, Fekadu Tefera, Alexander Golubtsov

Abstract: The African weakly electric elephantfish family Mormyridae comprises 22 genera and almost 230 species. Up-to-date cytogenetic information was available for 17 species representing 14 genera. Here we report chromosome number and morphology in Hyperopisus bebe (Lacepède, 1803) and Pollimyrus isidori (Valenciennes, 1847) collected from the White Nile system in southwestern Ethiopia. Both taxa displayed the diploid chromosome number 2n = 40, but they differed in fundamental numbers: FN = 66 in H. bebe and FN = 72 in P. isidori; previously the same diploid chromosome number 2n = 40 was reported in an undescribed species of Pollimyrus Taverne, 1971 (FN = 42) from the same region. Our results demonstrate that not only pericentric inversions, but fusions also played a substantial role in the evolution of the mormyrid karyotype structure. If the hypothesis that the karyotype structure with 2n = 50–52 and prevalence of the uni-armed chromosomes close to the ancestral condition for the family Mormyridae is correct, the most derived karyotype structures are found in the Mormyrus Linnaeus, 1758 species with 2n = 50 and the highest number of bi-armed elements in their compliments compared to all other mormyrids and in Pollimyrus isidori with the highest number of bi-armed elements among the mormyrids with 2n = 40.

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DOI: 10.3897/CompCytogen.v15.i4.68309

Authors: Eduard Petitpierre

Abstract: The meiotic systems of some Scottish individuals of the rare Chrysolina latecincta ssp. intermedia (Franz, 1938) have been analyzed from meiotic cells at diakinesis to study the types of chromosomal bivalents and the number and locations of their chiasmata. The mean number of unichiasmate was about two-thirds and that of bichiasmate bivalents about one-third. Most chiasmata were at distal positions and there were no pairwise statistically significant differences in the mean number of chiasmata and those of unichiasmate and bichiasmate bivalents between the three surveyed geographic sources of these Scottish individuals. However, pairwise significant differences were found in the mean number of proximal + interstitial chiasmata between Loch Etive (Argyllshire) and both Orkney and Shetland Islands individuals. The presumed higher values of genetic recombination due to the proximal + interstitial chiasmata with regard to the prevailing distal ones, might provide a slight selective advantage to the insular individuals against the more extreme climates of both islands compared with the Loch Etive site.

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DOI: 10.3897/CompCytogen.v15.i4.64350

Authors: Andrey Grishanin, Oksana Chinyakova

Abstract: The experimental results show that at doses of 20 Gy and 100 Gy, the development of Cyclops kolensis Lilljeborg, 1901 (Copepoda, Cyclopoida) embryos ceases at the 16-cell stage, without affecting the course of chromatin diminution. A dose of 200 Gy terminated the process of chromatin diminution in some of the embryos. These results support the hypothesis that cytoplasmic factors in the egg play an important role in the process of chromatin diminution.

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DOI: 10.3897/CompCytogen.v15.i3.71866

Authors: Valentina G. Kuznetsova, Ilya A. Gavrilov-Zimin, Snejana M. Grozeva, Natalia V. Golub

Abstract: This article is part (the 4th article) of the themed issue (a monograph) “Aberrant cytogenetic and reproductive patterns in the evolution of Paraneoptera”. The purpose of this article is to consider chromosome structure and evolution, chromosome numbers and sex chromosome systems, which all together constitute the chromosomal basis of reproduction and are essential for reproductive success. We are based on our own observations and literature data available for all major lineages of Paraneoptera including Zoraptera (angel insects), Copeognatha (=Psocoptera; bark lice), Parasita (=Phthiraptera s. str; true lice), Thysanoptera (thrips), Homoptera (scale insects, aphids, jumping plant-lice, whiteflies, and true hoppers), Heteroptera (true bugs), and Coleorrhyncha (moss bugs). Terminology, nomenclature, classification, and the study methods are given in the first paper of the issue (Gavrilov-Zimin et al. 2021).

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DOI: 10.3897/compcytogen.v15.i3.70362

Authors: Ilya A. Gavrilov-Zimin

Abstract: The paper is a third part of the themed issue “Aberrant cytogenetic and reproductive patterns in the evolution of Paraneoptera”, prepared by a Russian-Bulgarian research team on the basis of long-term collaborative studies. This chapter reviews different peculiar aberrations in the ontogenesis of Paraneoptera, such as the appearance of the quiescent apodal and/or arostrate instars, exuviatrial, pupillarial and pseudopupillarial development, cyclic parthenogenesis, etc. The material and methods, terminology and the nomenclature of the used taxonomic names are listed in the first chapter of the issue (Gavrilov-Zimin et al. 2021).

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