Latest Articles from Comparative Cytogenetics Latest 55 Articles from Comparative Cytogenetics https://compcytogen.pensoft.net/ Thu, 28 Mar 2024 18:18:46 +0200 Pensoft FeedCreator https://compcytogen.pensoft.net/i/logo.jpg Latest Articles from Comparative Cytogenetics https://compcytogen.pensoft.net/ Allium cytogenetics: a critical review on the Indian taxa https://compcytogen.pensoft.net/article/98903/ Comparative Cytogenetics 17: 129-156

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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Review Article Mon, 29 May 2023 15:42:26 +0300
Comparative karyotype analysis of eight Cucurbitaceae crops using fluorochrome banding and 45S rDNA-FISH https://compcytogen.pensoft.net/article/99236/ Comparative Cytogenetics 17: 31-58

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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Research Article Thu, 9 Feb 2023 17:40:12 +0200
A critical review on cytogenetics of Cucurbitaceae with updates on Indian taxa https://compcytogen.pensoft.net/article/79033/ Comparative Cytogenetics 16(2): 93-125

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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Review Article Tue, 26 Apr 2022 11:14:11 +0300
Cytotaxonomic investigations on species of genus Narcissus (Amaryllidaceae) from Algeria https://compcytogen.pensoft.net/article/78852/ Comparative Cytogenetics 16(1): 55-76

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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Research Article Tue, 5 Apr 2022 14:32:06 +0300
Distribution patterns of rDNA loci in the Schedonorus-Lolium complex (Poaceae) https://compcytogen.pensoft.net/article/79056/ Comparative Cytogenetics 16(1): 39-54

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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Research Article Thu, 24 Mar 2022 18:15:01 +0200
Comparative chromosome studies in species of subtribe Orchidinae (Orchidaceae) https://compcytogen.pensoft.net/article/75990/ Comparative Cytogenetics 15(4): 507-525

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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Research Article Fri, 17 Dec 2021 15:05:27 +0200
The Kengyilia hirsuta karyotype polymorphisms as revealed by FISH with tandem repeats and single-gene probes https://compcytogen.pensoft.net/article/71525/ Comparative Cytogenetics 15(4): 375-392

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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Research Article Wed, 3 Nov 2021 18:58:29 +0200
Genome size variation and karyotype diversity in eight taxa of Sorbus sensu stricto (Rosaceae) from China https://compcytogen.pensoft.net/article/58278/ Comparative Cytogenetics 15(2): 137-148

DOI: 10.3897/CompCytogen.v15.i2.58278

Authors: Jiabao Li, Kailin Zhu, Qin Wang, Xin Chen

Abstract: Eight taxa of Sorbus Linnaeus, 1753 sensu stricto (Rosaceae) from China have been studied karyologically through chromosome counting, chromosomal measurement and karyotype symmetry. Genome size was also estimated by flow cytometry. Six taxa, S. amabilis Cheng ex T.T.Yu et K.C.Kuan, 1963, S. hupehensis var. paucijuga (D.K. Zang et P.C. Huang, 1992) L.T. Lu, 2000, S. koehneana C.K. Schneider, 1906, S. pohuashanensis (Hance, 1875) Hedlund, 1901, S. scalaris Koehne, 1913 and S. wilsoniana C.K. Schneider, 1906 are diploids with 2n = 34, whereas two taxa, S. filipes Handel-Mazzetti,1933 and S. ovalis McAllister, 2005 are tetraploid with 2n = 68. In general, the chromosome size is mainly small, and karyotypes are symmetrical with predominance of metacentric chromosomes. Genome size variation of diploids and tetraploids is 1.401 pg –1.676 pg and 2.674 pg –2.684 pg, respectively. Chromosome numbers of S. amabilis and S. hupehensis var. paucijuga, and karyotype and genome size of eight taxa studied are reported for the first time. This study emphasised the reliability of flow cytometry in genome size determination to infer ploidy levels in Chinese native Sorbus species.

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Research Article Thu, 20 May 2021 17:09:02 +0300
Random chromosome distribution in the first meiosis of F1 disomic substitution line 2R(2D) x rye hybrids (ABDR, 4× = 28) occurs without bipolar spindle assembly https://compcytogen.pensoft.net/article/55827/ Comparative Cytogenetics 14(4): 453-482

DOI: 10.3897/compcytogen.v14.i4.55827

Authors: Dina B. Loginova, Anastasia A. Zhuravleva, Olga G. Silkova

Abstract: The assembly of the microtubule-based spindle structure in plant meiosis remains poorly understood compared with our knowledge of mitotic spindle formation. One of the approaches in our understanding of microtubule dynamics is to study spindle assembly in meiosis of amphyhaploids. Using immunostaining with phH3Ser10, CENH3 and α-tubulin-specific antibodies, we studied the chromosome distribution and spindle organisation in meiosis of F1 2R(2D)xR wheat-rye hybrids (genome structure ABDR, 4× = 28), as well as in wheat and rye mitosis and meiosis. At the prometaphase of mitosis, spindle assembly was asymmetric; one half of the spindle assembled before the other, with simultaneous chromosome alignment in the spindle mid-zone. At diakinesis in wheat and rye, microtubules formed a pro-spindle which was subsequently disassembled followed by a bipolar spindle assembly. In the first meiosis of hybrids 2R(2D)xR, a bipolar spindle was not found and the kinetochore microtubules distributed the chromosomes. Univalent chromosomes are characterised by a monopolar orientation and maintenance of sister chromatid and centromere cohesion. Presence of bivalents did not affect the formation of a bipolar spindle. Since the central spindle was absent, phragmoplast originates from “interpolar” microtubules generated by kinetochores. Cell plate development occurred with a delay. However, meiocytes in meiosis II contained apparently normal bipolar spindles. Thus, we can conclude that: (1) cohesion maintenance in centromeres and between arms of sister chromatids may negatively affect bipolar spindle formation in the first meiosis; (2) 2R/2D rye/wheat chromosome substitution affects the regulation of the random chromosome distribution in the absence of a bipolar spindle.

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Research Article Fri, 9 Oct 2020 13:14:36 +0300
Comparative molecular cytogenetic characterization of five wild Vigna species (Fabaceae) https://compcytogen.pensoft.net/article/51154/ Comparative Cytogenetics 14(2): 243-264

DOI: 10.3897/CompCytogen.v14i2.51154

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

Abstract: To extend our knowledge on karyotype variation of the genus Vigna Savi, 1824, the chromosomal organization of rRNA genes and fluorochrome banding patterns of five wild Vigna species were studied. Sequential combined PI (propidium iodide) and DAPI (4',6-diamidino-2-phenylindole) (CPD) staining and fluorescence in situ hybridization (FISH) with 5S and 45S rDNA probes were used to analyze the karyotypes of V. luteola (Jacquin, 1771) Bentham, 1959, V. vexillata (Linnaeus, 1753) A. Richard, 1845, V. minima (Roxburgh, 1832) Ohwi & H. Ohashi, 1969, V. trilobata (Linnaeus, 1753) Verdcourt, 1968, and V. caracalla (Linnaeus, 1753) Verdcourt,1970. For further phylogenetic analysis, genomic in situ hybridization (GISH) with the genomic DNA of V. umbellata (Thunberg, 1794) Ohwi & H.Ohashi, 1969 onto the chromosomes of five wild Vigna species was also performed. Detailed karyotypes were established for the first time using chromosome measurements, fluorochrome bands, and rDNA-FISH signals. All species had chromosome number 2n = 2x = 22, and symmetrical karyotypes that composed of only metacentric or metacentric and submetacentric chromosomes. CPD staining revealed all 45S rDNA sites in the five species analyzed, (peri)centromeric GC-rich heterochromatin in V. luteola, V. trilobata and V. caracalla, interstitial GC-rich and pericentromeric AT-rich heterochromatin in V. caracalla. rDNA-FISH revealed two 5S loci in V. caracalla and one 5S locus in the other four species; one 45S locus in V. luteola and V. caracalla, two 45S loci in V. vexillata and V. trilobata, and five 45S loci in V. minima. The karyotypes of the studied species could be clearly distinguished by the karyotypic parameters, and the patterns of the fluorochrome bands and the rDNA sites, which revealed high interspecific variation among the five species. The V. umbellata genomic DNA probe produced weak signals in all proximal regions of V. luteola and all (peri)centromeric regions of V. trilobata. The combined data demonstrate that distinct genome differentiation has occurred among the five species during evolution. The phylogenetic relationships between the five wild species and related cultivated species of Vigna are discussed based on our present and previous molecular cytogenetic data.

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Research Article Fri, 26 Jun 2020 22:57:45 +0300
Induction and evaluation of colchitetraploids of two species of Tinospora Miers, 1851 https://compcytogen.pensoft.net/article/33394/ Comparative Cytogenetics 14(2): 211-229

DOI: 10.3897/CompCytogen.v14i2.33394

Authors: Rakesh Kr. Thakur, Vijay Rani Rajpal, Satyawada Rama Rao, Apekshita Singh, Lata Joshi, Pankaj Kaushal, Soom Nath Raina

Abstract: Autotetraploidy, both natural and/or induced, has potential for genetic improvement of various crop species including that of medicinal importance. Tinospora cordifolia (Willdenow, 1806) Miers, 1851 ex Hooker et Thomson, 1855 and T. sinensis (Loureiro, 1790) Merrill, 1934 are two diploid species, which are dioecious, deciduous and climbing shrubs with high medicinal importance. Among the three methods used for induction of polyploidy by colchicine treatment, it was cotton swab method which successfully induced the polyploidy in both species. The morphological and cytogenetical features of the synthetic tetraploids were compared with their diploid counterparts. The tetraploids were morphologically distinct from diploid plants. They exhibited larger organs, such as stem, leaves, inflorescence, fruits, flowers and seeds. The tetraploids were characterized by the presence of low quadrivalent frequency and high bivalent average. Unequal distribution of chromosomes at anaphase I was found in 60% cells. The present study provides important information on the superiority of autotetraploids as compared to diploid counterparts in both species.

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Research Article Wed, 20 May 2020 14:32:19 +0300
Patterns of chromosomal variation in Mexican species of Aeschynomene (Fabaceae, Papilionoideae) and their evolutionary and taxonomic implications https://compcytogen.pensoft.net/article/47264/ Comparative Cytogenetics 14(1): 157-182

DOI: 10.3897/CompCytogen.v14i1.47264

Authors: Fernando Tapia-Pastrana, Alfonso Delgado-Salinas, Javier Caballero

Abstract: A cytogenetic analysis of sixteen taxa of the genus Aeschynomene Linnaeus, 1753, which includes species belonging to both subgenera Aeschynomene (Léonard, 1954) and Ochopodium (Vogel, 1838) J. Léonard, 1954, was performed. All studied species had the same chromosome number (2n = 20) but exhibited karyotype diversity originating in different combinations of metacentric, submetacentric and subtelocentric chromosomes, chromosome size and number of SAT chromosomes. The plasticity of the genomes included the observation in a taxon belonging to the subgenus Aeschynomene of an isolated spherical structure similar in appearance to the extra chromosomal circular DNA observed in other plant genera. By superimposing the karyotypes in a recent phylogenetic tree, a correspondence between morphology, phylogeny and cytogenetic characteristics of the taxa included in the subgenus Aeschynomene is observed. Unlike subgenus Aeschynomene, the species of Ochopodium exhibit notable karyotype heterogeneity. However the limited cytogenetic information recorded prevents us from supporting the proposal of their taxonomic separation and raise it to the genus category. It is shown that karyotype information is useful in the taxonomic delimitation of Aeschynomene and that the diversity in the diploid level preceded the hybridization/polyploidization demonstrated in the genus. The systematic implications of our results and their value can be extended to other Dalbergieae genera as knowledge about the chromosomal structure and its evolution increases.

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Research Article Wed, 11 Mar 2020 17:13:40 +0200
Relationship between meiotic behaviour and fertility in backcross-1 derivatives of the [(Gossypium hirsutum × G. thurberi)2 × G. longicalyx] trispecies hybrid https://compcytogen.pensoft.net/article/47231/ Comparative Cytogenetics 14(1): 75-95

DOI: 10.3897/CompCytogen.v14i1.47231

Authors: N’guessan Olivier Konan, Guy Mergeai

Abstract: Wild cotton species are an important source of desirable genes for genetic improvement of cultivated cotton Gossypium hirsutum Linnaeus, 1763. For the success of such an improvement, chromosome pairings and recombinations in hybrids are fundamental. The wild African species G. longicalyx Hutchinson & Lee, 1958 could be used as donor of the desirable trait of fiber fineness. Twelve BC1 plants obtained from the backcrossing of [(G. hirsutum × G. thurberi Todaro, 1877)2 × G. longicalyx] (AhDhD1F1, 2n = 4x = 52) trispecies hybrid (HTL) by G. hirsutum (cv. C2) (AhAhDhDh, 2n = 4x = 52) were investigated for meiotic behaviour and plant fertility. Their chromosome associations varied as follows: (2.5 to 11.5) I + (17 to 22) II + (0.31 to 1.93) III + (0.09 to 1.93) IV + (0 to 0.07) V + (0 to 0.14) VI. Their pollen fertility ranged from 4.67 to 32.10 %. Only four BC1 plants produced a few seeds through self-pollination. The remaining BC1 were totally self-sterile and usually presented the highest number of univalents. All BC1 materials produced BC2 seeds (0.44 to 6.50 seeds per backcross) with the number of seeds negatively correlated with the number of univalents (R2 = 0.45, P < 0.05). Most BC1 plants gave significantly finer fiber compared to the cultivated G. hirsutum. SSR markers showed a segregation of wild alleles among the backcross derivatives and Genomic in situ hybridization (GISH) revealed presence of entire chromosomes of G. longicalyx as well as recombinant chromosomes in the backcross derivatives. The significance and details of these results are presented and the prospects of successfully exploiting these plant materials are discussed.

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Research Article Tue, 28 Jan 2020 14:49:19 +0200
Cytogenetic and pollen identification of genus Gagnepainia (Zingiberaceae) in Thailand https://compcytogen.pensoft.net/article/47346/ Comparative Cytogenetics 14(1): 11-25

DOI: 10.3897/CompCytogen.v14i1.47346

Authors: Paramet Moonkaew, Nattapon Nopporncharoenkul, Thaya Jenjittikul, Puangpaka Umpunjun

Abstract: Gagnepainia godefroyi K. Schumann, 1904 and G. harmandii K. Schumann, 1904 belong to the genus Gagnepainia K. Schumann, 1904 of the Ginger family. They have the potential to be developed as medicinal and attractive ornamental plants. To date, the knowledge on the cytological and reproductive aspects of Gagnepainia have not been publicly available. Therefore, the aims of this research are to investigate the cytogenetic and pollen characters of Gagnepainia species using light, fluorescence, and scanning electron microscopes. The regular meiotic figures of 15 bivalents are found in both species and presented for the first time. These evidences indicate that Gagnepainia is diploid and contains 2n = 2x = 30 with basic number of x = 15. The mean nuclear DNA contents range from 1.986 pg in Gagnepainia sp., 2.090 pg in G. godefroyi to 2.195 pg in G. harmandii. Pollens of all species are monad, inaperturate, prolate with bilateral symmetry, and thick wall with fossulate exine sculpturing. The pollen size of G. harmandii (74.506 ± 5.075 μm, 56.082 ± 6.459 μm) is significantly larger than that of G. godefroyi (59.968 ± 3.484 μm, 45.439 ± 2.870 μm). Both 2C DNA content and pollen size are the effective characteristics for species discrimination. The reproductive evidence of high meiotic stability and normal pollen production indicate that both Gagnepainia species have high fertility and seed productivity, which are in accordance with the broad distribution. The present study provides good cytogenetic and pollen characters not only for plant identification, but also plant fertility assessment through plant genetic resource management and improvement of Gagnepainia.

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Research Article Mon, 13 Jan 2020 13:26:26 +0200
Cytogenetic and molecular characteristics of rye genome in octoploid triticale (× Triticosecale Wittmack) https://compcytogen.pensoft.net/article/39576/ Comparative Cytogenetics 13(4): 423-434

DOI: 10.3897/CompCytogen.v13i4.39576

Authors: Elena V. Evtushenko, Yulia A. Lipikhina, Petr I. Stepochkin, Alexander V. Vershinin

Abstract: Alloploidization resulting from remote (interspecific or intergeneric) hybridization is one of the main factors in plant evolution, leading to the formation of new species. Triticale (× Triticosecale Wittmack, 1889) is the first artificial species created by crossing wheat (Triticum spp.) and rye (Secale cereale Linnaeus, 1753) and has a great potential as a grain and forage crop. Remote hybridization is a stress factor that causes a rapid reorganization of the parental genomes in hybrid progeny (“genomic shock”) and is accompanied by abnormalities in the chromosome set of hybrids. The formation of the hybrid genome and its subsequent stabilization are directly related to the normalization of meiosis and the correct chromosome segregation. The aim of this work was to cytogenetically characterize triticale (× Triticosecale rimpaui Wittmack, 1899, AABBDDRR) obtained by crossing Triticum aestivum Linnaeus, 1753. Triple Dirk D × Secale cereale L. Korotkostebel’naya 69 in F3–F6 generations of hybrids, and to trace the process of genetic stabilization of hybrid genomes. Also, a comparative analysis of the nucleotide sequences of the centromeric histone CENH3 genes was performed in wheat-rye allopolyploids of various ploidy as well as their parental forms. In the hybrid genomes of octoploid triticale an increased expression of the rye CENH3 variants was detected. The octoploid triticale plants contain complete chromosome sets of the parental subgenomes maintaining the chromosome balance and meiotic stability. For three generations the percentage of aneuploids in the progeny of such plants has been gradually decreasing, and they maintain a complete set of the paternal rye chromosomes. However, the emergence of hexaploid and new aneuploid plants in F5 and F6 generations indicates that stabilization of the hybrid genome is not complete yet. This conclusion was confirmed by the analysis of morphological features in hybrid plants: the progeny of one plant having the whole chromosome sets of parental subgenomes showed significant morphological variations in awn length and spike density. Thus, we expect that the results of our karyotyping of octoploid triticales obtained by crossing hexaploid wheat to diploid rye supplemented by comparative analysis of CENH3 sequences will be applicable to targeted breeding of stable octo- and hexaploid hybrids.

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Research Article Mon, 16 Dec 2019 12:31:14 +0200
Molecular-cytogenetic analysis of diploid wheatgrass Thinopyrum bessarabicum (Savul. and Rayss) A. Löve https://compcytogen.pensoft.net/article/36879/ Comparative Cytogenetics 13(4): 389-402

DOI: 10.3897/CompCytogen.v13i4.36879

Authors: Ekaterina D. Badaeva, Sergei A. Surzhikov, Alexander V. Agafonov

Abstract: Thinopyrum bessarabicum (T. Săvulescu & T. Rayss, 1923) A. Löve, 1980 is diploid (2n=2x=14, JJ or EbEb), perennial self-fertilizing rhizomatous maritime beach grass, which is phylogenetically close to another diploid wheatgrass species, Agropyron elongatum (N. Host, 1797) P. de Beauvois, 1812. The detailed karyotype of Th. bessarabicum was constructed based on FISH with six DNA probes representing 5S and 45S rRNA gene families and four tandem repeats. We found that the combination of pAesp_SAT86 (= pTa-713) probe with pSc119.2 or pAs1/ pTa-535 allows the precise identification of all J-genome chromosomes. Comparison of our data with the results of other authors showed that karyotypically Th. bessarabicum is distinct from A. elongatum. On the other hand, differences between the J-genome chromosomes of Th. bessarabicum and the chromosomes of hexaploid Th. intermedium (N. Host, 1797) M. Barkworth & D.R. Dewey, 1985 and decaploid Th. ponticum (J. Podpěra, 1902) Z.–W. Liu & R.–C. Wang, 1993 in the distribution of rDNA loci and hybridization patterns of pSc119.2 and pAs1 probes could be an indicative of (1) this diploid species was probably not involved in the origin of these polyploids or (2) it could has contributed the J-genome to Th. intermedium and Th. ponticum, but it was substantially modified over the course of speciation

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Research Article Tue, 3 Dec 2019 16:39:45 +0200
Development of new cytogenetic markers for Thinopyrum ponticum (Podp.) Z.-W. Liu & R.-C. Wang https://compcytogen.pensoft.net/article/36112/ Comparative Cytogenetics 13(3): 231-243

DOI: 10.3897/CompCytogen.v13i3.36112

Authors: Pavel Yu. Kroupin, Victoria M. Kuznetsova, Ekaterina A. Nikitina, Yury Ts. Martirosyan, Gennady I. Karlov, Mikhail G. Divashuk

Abstract: Thinopyrum ponticum (Podpěra, 1902) Z.-W. Liu & R.-C.Wang, 1993 is an important polyploid wild perennial Triticeae species that is widely used as a source of valuable genes for wheat but its genomic constitution has long been debated. For its chromosome identification, only a limited set of FISH probes has been used. The development of new cytogenetic markers for Th. ponticum chromosomes is of great importance both for cytogenetic characterization of wheat-wheatgrass hybrids and for fundamental comparative studies of phylogenetic relationships between species. Here, we report on the development of five cytogenetic markers for Th. ponticum based on repetitive satellite DNA of which sequences were selected from the whole genome sequence of Aegilops tauschii Cosson, 1849. Using real-time quantitative PCR we estimated the abundance of the found repeats: P720 and P427 had the highest abundance and P132, P332 and P170 had lower quantity in Th. ponticum genome. Using fluorescence in situ hybridization (FISH) we localized five repeats to different regions of the chromosomes of Th. ponticum. Using reprobing multicolor FISH we colocalized the probes between each other. The distribution of these found repeats in the Triticeae genomes and its usability as cytogenetic markers for chromosomes of Th. ponticum are discussed.

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Research Article Tue, 13 Aug 2019 14:34:31 +0300
New chromosome counts and genome size estimates for 28 species of Taraxacum sect. Taraxacum https://compcytogen.pensoft.net/article/27307/ Comparative Cytogenetics 12(3): 403-420

DOI: 10.3897/CompCytogen.v12i3.27307

Authors: Petra Macháčková, Ľuboš Majeský, Michal Hroneš, Eva Hřibová, Bohumil Trávníček, Radim J. Vašut

Abstract: The species-rich and widespread genus Taraxacum F. H. Wiggers, 1780 (Asteraceae subfamily Cichorioideae) is one of the most taxonomically complex plant genera in the world, mainly due to its combination of different sexual and asexual reproduction strategies. Polyploidy is usually confined to apomictic microspecies, varying from 3x to 6x (rarely 10x). In this study, we focused on Taraxacum sect. Taraxacum (= T. sect. Ruderalia; T. officinale group), i.e., the largest group within the genus. We counted chromosome numbers and measured the DNA content for species sampled in Central Europe, mainly in Czechia. The chromosome number of the 28 species (T. aberrans Hagendijk, Soest & Zevenbergen, 1974, T. atroviride Štěpánek & Trávníček, 2008, T. atrox Kirschner & Štěpánek, 1997, T. baeckiiforme Sahlin, 1971, T. chrysophaenum Railonsala, 1957, T. coartatum G.E. Haglund, 1942, T. corynodes G.E. Haglund, 1943, T. crassum H. Øllgaard & Trávníček, 2003, T. deltoidifrons H. Øllgaard, 2003, T. diastematicum Marklund, 1940, T. gesticulans H. Øllgaard, 1978, T. glossodon Sonck & H. Øllgaard, 1999, T. guttigestans H. Øllgaard in Kirschner & Štěpánek, 1992, T. huelphersianum G.E. Haglund, 1935, T. ingens Palmgren, 1910, T. jugiferum H. Øllgaard, 2003, T. laticordatum Marklund, 1938, T. lojoense H. Lindberg, 1944 (= T. debrayi Hagendijk, Soest & Zevenbergen, 1972, T. lippertianum Sahlin, 1979), T. lucidifrons Trávníček, ineditus, T. obtusifrons Marklund, 1938, T. ochrochlorum G.E. Haglund, 1942, T. ohlsenii G.E. Haglund, 1936, T. perdubium Trávníček, ineditus, T. praestabile Railonsala, 1962, T. sepulcrilobum Trávníček, ineditus, T. sertatum Kirschner, H. Øllgaard & Štěpánek, 1997, T. subhuelphersianum M.P. Christiansen, 1971, T. valens Marklund, 1938) is 2n = 3x = 24. The DNA content ranged from 2C = 2.60 pg (T. atrox) to 2C = 2.86 pg (T. perdubium), with an average value of 2C = 2.72 pg. Chromosome numbers are reported for the first time for 26 species (all but T. diastematicum and T. obtusifrons), and genome size estimates for 26 species are now published for the first time.

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Research Article Tue, 18 Sep 2018 18:34:07 +0300
Variation in chromosome number and breeding systems: implications for diversification in Pachycereus pringlei (Cactaceae) https://compcytogen.pensoft.net/article/21554/ Comparative Cytogenetics 12(1): 61-82

DOI: 10.3897/compcytogen.v12i1.21554

Authors: Carina Gutiérrez-Flores, José L. León-de la Luz, Francisco J. García-De León, J. Hugo Cota-Sánchez

Abstract: Polyploidy, the possession of more than two sets of chromosomes, is a major biological process affecting plant evolution and diversification. In the Cactaceae, genome doubling has also been associated with reproductive isolation, changes in breeding systems, colonization ability, and speciation. Pachycereus pringlei (S. Watson, 1885) Britton & Rose, 1909, is a columnar cactus that has long drawn the attention of ecologists, geneticists, and systematists due to its wide distribution range and remarkable assortment of breeding systems in the Mexican Sonoran Desert and the Baja California Peninsula (BCP). However, several important evolutionary questions, such as the distribution of chromosome numbers and whether the diploid condition is dominant over a potential polyploid condition driving the evolution and diversity in floral morphology and breeding systems in this cactus, are still unclear. In this study, we determined chromosome numbers in 11 localities encompassing virtually the entire geographic range of distribution of P. pringlei. Our data revealed the first diploid (2n = 22) count in this species restricted to the hermaphroditic populations of Catalana (ICA) and Cerralvo (ICE) Islands, whereas the tetraploid (2n = 44) condition is consistently distributed throughout the BCP and mainland Sonora populations distinguished by a non-hermaphroditic breeding system. These results validate a wider distribution of polyploid relative to diploid individuals and a shift in breeding systems coupled with polyploidisation. Considering that the diploid base number and hermaphroditism are the proposed ancestral conditions in Cactaceae, we suggest that ICE and ICA populations represent the relicts of a southern diploid ancestor from which both polyploidy and unisexuality evolved in mainland BCP, facilitating the northward expansion of this species. This cytogeographic distribution in conjunction with differences in floral attributes suggests the distinction of the diploid populations as a new taxonomic entity. We suggest that chromosome doubling in conjunction with allopatric distribution, differences in neutral genetic variation, floral traits, and breeding systems has driven the reproductive isolation, evolution, and diversification of this columnar cactus.

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Research Article Tue, 13 Feb 2018 10:55:16 +0200
Cytogeography of Callisia section Cuthbertia (Commelinaceae) https://compcytogen.pensoft.net/article/11984/ Comparative Cytogenetics 11(4): 553-577

DOI: 10.3897/compcytogen.v11i4.11984

Authors: Iwan E. Molgo, Douglas E. Soltis, Pamela S. Soltis

Abstract: Determining the distribution of cytotypes across the geographic distribution of polyploid complexes can provide valuable information about the evolution of biodiversity. Here, the phytogeography of cytotypes in section Cuthbertia (Small, 1903) Hunt, 1986 is investigated. A total of 436 voucher specimens was georeferenced; 133 new specimens were collected. Based on flow cytometry data, DNA content of all cytotypes in section Cuthbertia was estimated. Utilizing chromosome counts and flow cytometric analysis, cytotype distribution maps were generated. Two disjunct groups of populations of diploid Callisia graminea (Small, 1903) Tucker, 1989 were discovered; tetraploid C. graminea ranges broadly from the coastal plain of North Carolina through central Florida. One hexaploid C. graminea individual was recorded in South Carolina, and numerous individuals of hexaploid C. graminea were found in central Florida. Diploid C. ornata (Small, 1933) Tucker, 1989 occurs in eastern Florida; previously unknown tetraploid and hexaploid populations of C. ornata were discovered in western and central Florida, respectively. Diploid C. rosea (Ventenat, 1800) Hunt, 1986 occurs in Georgia and the Carolinas, with populations occurring on both sides of the Fall Line. The cytotype and species distributions in Callisia are complex, and these results provide hypotheses, to be tested with morphological and molecular data, about the origins of the polyploid cytotypes.

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Research Article Fri, 1 Sep 2017 11:01:25 +0300
Cestrum strigilatum (Ruiz & Pavón, 1799) B chromosome shares repetitive DNA sequences with A chromosomes of different Cestrum (Linnaeus, 1753) species https://compcytogen.pensoft.net/article/13418/ Comparative Cytogenetics 11(3): 511-524

DOI: 10.3897/CompCytogen.v11i3.13418

Authors: André Luís Laforga Vanzela, Adriano Alves de Paula, Carolina Cristina Quintas, Thiago Fernandes, Joana Neres da Cruz Baldissera, Thaissa Boldieri de Souza

Abstract: Species of Cestrum (Linnaeus, 1753) have shown large diversity in the accumulation and distribution of repetitive DNA families, and B chromosomes have been described in seven species. Some types of repetitive DNA were identified in A and B chromosomes in species of this plant group, such as AT-rich SSR, 35S and 5S rDNA, C-Giemsa and C-CMA/DAPI bands and retrotransposons. To increase our understanding of the relationships of A and B chromosomes, the B of C. strigilatum Ruiz & Pavón, 1799 was microdissected, amplified and hybridized in situ against chromosomes of this species, and in six other species of this genus. FISH signals were observed in whole the B of C. strigilatum, including stretches of A chromosomes, as well as in some A chromosomes of all tested species. A strong FISH signal was seen adjacent to the 5S rDNA in the proximal region of pair 8 of all species and, due to this, we have searched for 5S rDNA fragments in the microdissected B chromosome. PCR and sequencing data evidenced 5S rDNA deletion along evolutionary pathways of the B of C. strigilatum. Although A and B chromosomes displayed redundancy in the repetitive DNA families in different species, the B of C. strigilatum seemed to differ from those Bs of other Cestrum species by the loss of rDNA fractions. A possible origin of Bs in Cestrum was discussed.

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Research Article Thu, 3 Aug 2017 11:08:34 +0300
Chromosomal constitutions of five wheat – Elytrigia elongata partial amphiploids as revealed by GISH, multicolor GISH and FISH https://compcytogen.pensoft.net/article/11883/ Comparative Cytogenetics 11(3): 525-540

DOI: 10.3897/CompCytogen.v11i3.11883

Authors: Fang He, Yuhai Wang, Yinguang Bao, Yingxue Ma, Xin Wang, Xingfeng Li, Honggang Wang

Abstract: A combination of meiotic pairing analysis and in situ hybridization (genomic in situ hybridization [GISH], multicolor GISH [mcGISH] and fluorescence in situ hybridization [FISH]) of five Triticum aestivum (Linnaeus, 1753) - Elytrigia elongata (Podpěra, 1902) (2n = 10x = 70) amphiploids was employed to investigate the genomic constitution and relationships between wheat and alien chromosomes. GISH, multicolor GISH and FISH patterns of mitotic chromosomes indicate that the genomic constitution of the five partial amphiploids (XY693, XY7430, SN19, SN20 and SN122) are 14A + 12B + 14D + 8Js + 8J, 12A + 16B + 14D + 2St + 8Js + 2J + 2 W-E, 14A + 14B + 14D + 4St + 8Js, 14A + 14B + 14D + 2St + 10Js + 2J, and 14A + 14B + 14D + 2St + 8Js + 4J, respectively. Analysis of meiotic chromosome pairing in the F1 hybrids between these five partial amphiploids suggests that SN20 and SN122 are the most closely related amphiploids and are somewhat related with XY693 and XY7430. However, the alien chromosome constitutions of SN19 differed from the other four amphiploids. In addition, a new pairing between wheat and E. elongata chromosomes was distinguished in some cells of the hybrids SN19 × XY7430, SN20 × XY7430 and SN122 × XY7430.

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Research Article Thu, 3 Aug 2017 11:07:41 +0300
The Cerrado (Brazil) plant cytogenetics database https://compcytogen.pensoft.net/article/11395/ Comparative Cytogenetics 11(2): 285-297

DOI: 10.3897/CompCytogen.v11i2.11395

Authors: Fernando Roa, Mariana Pires de Campos Telles

Abstract: Cerrado is a biodiversity hotspot that has lost ca. 50% of its original vegetation cover and hosts ca. 11,000 species belonging to 1,423 genera of phanerogams. For a fraction of those species some cytogenetic characteristics like chromosome numbers and C-value were available in databases, while other valuable information such as karyotype formula and banding patterns are missing. In order to integrate and share all cytogenetic information published for Cerrado species, including frequency of cytogenetic attributes and scientometrics aspects, Cerrado plant species were searched in bibliographic sources, including the 50 richest genera (with more than 45 taxa) and 273 genera with only one species in Cerrado. Determination of frequencies and the database website (http://cyto.shinyapps.io/cerrado) were developed in R. Studies were pooled by employed technique and decade, showing a rise in non-conventional cytogenetics since 2000. However, C-value estimation, heterochromatin staining and molecular cytogenetics are still not common for any family. For the richest and best sampled families, the following modal 2n counts were observed: Oxalidaceae 2n = 12, Lythraceae 2n = 30, Sapindaceae 2n = 24, Solanaceae 2n = 24, Cyperaceae 2n = 10, Poaceae 2n = 20, Asteraceae 2n = 18 and Fabaceae 2n = 26. Chromosome number information is available for only 16.1% of species, while there are genome size data for only 1.25%, being lower than the global percentages. In general, genome sizes were small, ranging from 2C = ca. 1.5 to ca. 3.5 pg. Intra-specific 2n number variation and higher 2n counts were mainly related to polyploidy, which relates to the prevalence of even haploid numbers above the mode of 2n in most major plant clades. Several orphan genera with almost no cytogenetic studies for Cerrado were identified. This effort represents a complete diagnosis for cytogenetic attributes of plants of Cerrado.

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Data Paper Tue, 25 Apr 2017 14:19:46 +0300
Karyotype characterization and comparison of three hexaploid species of Bromus Linnaeus, 1753 (Poaceae) https://compcytogen.pensoft.net/article/11572/ Comparative Cytogenetics 11(2): 213-223

DOI: 10.3897/CompCytogen.v11i2.11572

Authors: Leonardo Luís Artico, Ana Cristina Mazzocato, Juliano Lino Ferreira, Carlos Roberto Carvalho, Wellington Ronildo Clarindo

Abstract: Chromosome morphometry and nuclear DNA content are useful data for cytotaxonomy and to understand the evolutionary history of different taxa. For the genus Bromus Linnaeus, 1753, distinct ploidy levels have been reported, occurring from diploid to duodecaploid species. The geographic distribution of Bromus species has been correlated with chromosome number and ploidy level. In this study, the aims were to determine the nuclear genome size and characterize the karyotype of the South American Bromus species: Bromus auleticus Trinius ex Nees, 1829, Bromus brachyanthera Döll, 1878 and Bromus catharticus Vahl, 1791. The mean nuclear 2C value ranged from 2C = 12.64 pg for B. catharticus to 2C = 17.92 pg for B. auleticus, meaning a maximum variation of 2C = 5.28 pg, equivalent to 41.70%. Despite this significant difference in 2C value, the three species exhibit the same chromosome number, 2n = 6x = 42, which confirms their hexaploid origin. Corroborating the genome size, the chromosome morphometry (total, short- and long-arm length) and, consequently, the class differed among the karyotypes of the species. Based on the first karyograms for these Bromus species, some morphologically similar and several distinct chromosome pairs were found. Therefore, the karyotype characterization confirmed the hexaploid origin of the studied Bromus species, which differ in relation to the karyogram and the nuclear 2C value. Considering this, cytogenetics and flow cytometry can be used to discriminate Bromus species, contributing to taxonomy and systematic studies and providing information on the evolutionary history of this taxa.

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Research Article Fri, 7 Apr 2017 11:25:07 +0300
First karyotype description and nuclear 2C value for Myrsine (Primulaceae): comparing three species https://compcytogen.pensoft.net/article/11601/ Comparative Cytogenetics 11(1): 163-177

DOI: 10.3897/CompCytogen.v11i1.11601

Authors: Renata Flávia de Carvalho, Paulo Marcos Amaral-Silva, Micheli Sossai Spadeto, Andrei Caíque Pires Nunes, Tatiana Tavares Carrijo, Carlos Roberto Carvalho, Wellington Ronildo Clarindo

Abstract: Cytogenetic studies in Primulaceae are mostly available for herbaceous species, and are focused on the chromosome number determination. An accurate karyotype characterization represents a starting point to know the morphometry and class of the chromosomes. Comparison among species within Myrsine, associating these data with the nuclear 2C value, can show changes that led the karyotype evolution. Here, we studied three Myrsine species [Myrsine coriacea (Swartz, 1788) Brown ex Roemer et Schultes, 1819, Myrsine umbellata Martius, 1841 and Myrsine parvifolia Candolle, 1841] that show different abilities to occupy the varied types of vegetation within the Brazilian Atlantic Forest. Cytogenetic characterization showed some individuals with 2n = 45 chromosomes for M. parvifolia and M. coriacea, with most individuals of the three species having 2n = 46. The first karyograms for Myrsine were assembled and presented morphologically identical and distinct chromosome pairs. In addition, differences in the mean 2C nuclear value and chromosome morphometry were found. Therefore, the first description of the Myrsine karyotype has been presented, as well as the nuclear 2C value. The procedures can be applied to other Myrsine species for future investigations in order to better understand its effects on the differential spatial occupation abilities shown by the species in Brazilian Atlantic Forest.

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Research Article Mon, 13 Mar 2017 11:51:41 +0200
Genomic characterisation of Arachis porphyrocalyx (Valls & C.E. Simpson, 2005) (Leguminosae): multiple origin of Arachis species with x = 9 https://compcytogen.pensoft.net/article/10339/ Comparative Cytogenetics 11(1): 29-43

DOI: 10.3897/CompCytogen.v11i1.10339

Authors: Silvestri María Celeste, Alejandra Marcela Ortiz, Germán Ariel Robledo, José Francisco Montenegro Valls, Graciela Inés Lavia

Abstract: The genus Arachis Linnaeus, 1753 comprises four species with x = 9, three belong to the section Arachis: Arachis praecox (Krapov. W.C. Greg. & Valls, 1994), Arachis palustris (Krapov. W.C. Greg. & Valls, 1994) and Arachis decora (Krapov. W.C. Greg. & Valls, 1994) and only one belongs to the section Erectoides: Arachis porphyrocalyx (Valls & C.E. Simpson, 2005). Recently, the x = 9 species of section Arachis have been assigned to G genome, the latest described so far. The genomic relationship of A. porphyrocalyx with these species is controversial. In the present work, we carried out a karyotypic characterisation of A. porphyrocalyx to evaluate its genomic structure and analyse the origin of all x = 9 Arachis species. Arachis porphyrocalyx showed a karyotype formula of 14m+4st, one pair of A chromosomes, satellited chromosomes type 8, one pair of 45S rDNA sites in the SAT chromosomes, one pair of 5S rDNA sites and pericentromeric C-DAPI+ bands in all chromosomes. Karyotype structure indicates that A. porphyrocalyx does not share the same genome type with the other three x = 9 species and neither with the remaining Erectoides species. Taking into account the geographic distribution, morphological and cytogenetic features, the origin of species with x = 9 of the genus Arachis cannot be unique; instead, they originated at least twice in the evolutionary history of the genus.

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Research Article Mon, 9 Jan 2017 18:58:00 +0200
Distribution, karyomorphology, and morphology of Aspidistra subrotata (Asparagaceae) at different ploidy levels in limestone areas of Asia https://compcytogen.pensoft.net/article/9803/ Comparative Cytogenetics 11(1): 1-13

DOI: 10.3897/CompCytogen.v11i1.9803

Authors: Jian-she Chen, Qi Gao, Hao Zhou, Yu-song Huang, Mikinori Ogisu, Ming Cao

Abstract: Aspidistra subrotata Y. Wan & C.C. Huang, 1987 is considered for the first time as a widespread polyploidy complex in the genus Aspidistra Ker Gawler, 1823 from limestone areas of Asia. The chromosome number of the tetraploid is 2n = 76 and the karyotype is formulated as 2n = 44 m + 8 sm + 24 st, while the chromosome number of the diploid is 2n = 38 and the karyotype formula 2n = 22 m + 4 sm + 12 st. In our studies, diploids occupy broader geographical and environmental niche spaces than tetraploids. Although the leaf-shape of A. subrotata varies quantitatively between and within diploid and/or tetraploid population(s), no obvious discontinuity in the width of leaf has been observed. The tetraploid plants may be distinguished from the diploid plants by their rigid petioles as well as thick deep green lamina. A. subrotata is therefore an interesting material to explore the formation and the evolutionary dynamics of a natural polyploid complex from limestone areas of the tropical regions.

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Research Article Mon, 9 Jan 2017 18:56:00 +0200
Unraveling the karyotype structure of the spurges Euphorbia hirta Linnaeus, 1753 and E. hyssopifolia Linnaeus, 1753 (Euphorbiaceae) using genome size estimation and heterochromatin differentiation https://compcytogen.pensoft.net/article/8193/ Comparative Cytogenetics 10(4): 657-669

DOI: 10.3897/CompCytogen.v10i4.8193

Authors: Karla C. B. Santana, Diego S. B. Pinangé, Santelmo Vasconcelos, Ana Rafaela Oliveira, Ana Christina Brasileiro-Vidal, Marccus V. Alves, Ana Maria Benko-Iseppon

Abstract: Euphorbia Linnaeus, 1753 (Euphorbiaceae) is one of the most diverse and complex genera among the angiosperms, showing a huge diversity in morphologic traits and ecologic patterns. In order to improve the knowledge of the karyotype organization of Euphorbia hirta (2n = 18) and E. hyssopifolia (2n = 12), cytogenetic studies were performed by means of conventional staining with Giemsa, genome size estimations with flow cytometry, heterochromatin differentiation with chromomycin A3 (CMA) and 4’,6-diamidino-2-phenylindole (DAPI) and Giemsa C-banding, fluorescent in situ hybridization (FISH) with 45S and 5S rDNA probes, and impregnation with silver nitrate (AgNO3). Our results revealed small metacentric chromosomes, CMA+/DAPI0 heterochromatin in the pericentromeric regions of all chromosomes and CMA+/DAPI− in the distal part of chromosome arms carriers of nucleolar organizing regions (NORs). The DNA content measurements revealed small genomes for both species: E. hirta with 2C = 0.77 pg and E. hyssopifolia with 2C = 1.41 pg. After FISH procedures, E. hirta, and E. hyssopifolia presented three and four pairs of terminal 45S rDNA sites, respectively, colocalizing with CMA+ heterochromatic blocks, besides only one interstitial pair of 5S rDNA signals. Additionally, the maximum number of active NORs agreed with the total number of observed 45S rDNA sites. This work represents the first analysis using FISH in the subfamily Euphorbioideae, revealing a significant number of chromosomal markers, which may be very helpful to understand evolutionary patterns among Euphorbia species.

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Short Communication Thu, 1 Dec 2016 18:07:34 +0200
Towards a FISH-based karyotype of Rosa L. (Rosaceae) https://compcytogen.pensoft.net/article/9536/ Comparative Cytogenetics 10(4): 543-554

DOI: 10.3897/CompCytogen.v10i4.9536

Authors: Ilya V. Kirov, Katrijn Van Laere, Nadine Van Roy, Ludmila I. Khrustaleva

Abstract: The genus Rosa Linnaeus, 1753 has important economic value in ornamental sector and many breeding activities are going on supported by molecular studies. However, the cytogenetic studies of rose species are scarce and mainly focused on chromosome counting and chromosome morphology-based karyotyping. Due to the small size of the chromosomes and a high frequency of polyploidy in the genus, karyotyping is very challenging for rose species and requires FISH-based cytogenetic markers to be applied. Therefore, in this work the aim is to establish a FISH-based karyotype for Rosa wichurana (Crépin, 1888), a rose species with several benefits for advanced molecular cytogenetic studies of genus Rosa (Kirov et al. 2015a). It is shown that FISH signals from 5S, 45S and an Arabidopsis-type telomeric repeat are distributed on five (1, 2, 4, 5 and 7) of seven chromosome pairs. In addition, it is demonstrated that the interstitial telomeric repeat sequences (ITR) are located in the centromeric regions of four chromosome pairs. Using low hybridization stringency for ITR visualization, we showed that the number of ITR signals increases four times (1–4 signals). This study is the first to propose a FISH-based R. wichurana karyotype for the reliable identification of chromosomes. The possible origin of R. wichuranaITR loci is discussed.

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Research Article Fri, 4 Nov 2016 18:41:21 +0200
Chromosomal organization of repetitive DNAs in Hordeum bogdanii and H. brevisubulatum (Poaceae) https://compcytogen.pensoft.net/article/9666/ Comparative Cytogenetics 10(4): 465-481

DOI: 10.3897/CompCytogen.v10i4.9666

Authors: Quanwen Dou, Ruijuan Liu, Feng Yu

Abstract: Molecular karyotypes of H. bogdanii Wilensky, 1918 (2n = 14), and H. brevisubulatum Link, 1844 ssp. brevisubulatum (2n = 28), were characterized by physical mapping of several repetitive sequences. A total of 18 repeats, including all possible di- or trinucleotide SSR (simple sequence repeat) motifs and satellite DNAs, such as pAs1, 5S rDNA, 45S rDNA, and pSc119.2, were used as probes for fluorescence in situ hybridization on root-tip metaphase chromosomes. Except for the SSR motifs AG, AT and GC, all the repeats we examined produced detectable hybridization signals on chromosomes of both species. A detailed molecular karyotype of the I genome of H. bogdanii is described for the first time, and each repetitive sequence is physically mapped. A high degree of chromosome variation, including aneuploidy and structural changes, was observed in H. brevisubulatum. Although the distribution of repeats in the chromosomes of H. brevisubulatum is different from that of H. bogdanii, similar patterns between the two species imply that the autopolyploid origin of H. brevisubulatum is from a Hordeum species with an I genome. A comparison of the I genome and the other Hordeum genomes, H, Xa and Xu, shows that colocalization of motifs AAC, ACT and CAT and colocalization of motifs AAG and AGG are characteristic of the I genome. In addition, we discuss the evolutionary significance of repeats in the genome during genome differentiation.

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Research Article Fri, 7 Oct 2016 18:35:40 +0300
First detailed karyo-morphological analysis and molecular cytological study of leafy cardoon and globe artichoke, two multi-use Asteraceae crops https://compcytogen.pensoft.net/article/9469/ Comparative Cytogenetics 10(3): 447-463

DOI: 10.3897/CompCytogen.v10i3.9469

Authors: Debora Giorgi, Gianmarco Pandozy, Anna Farina, Valentina Grosso, Sergio Lucretti, Andrea Gennaro, Paola Crinò, Francesco Saccardo

Abstract: Traditionally globe artichoke and leafy cardoon have been cultivated for use as vegetables but these crops are now finding multiple new roles in applications ranging from paper production to cheese preparation and biofuel use, with interest in their functional food potential. So far, their chromosome complements have been poorly investigated and a well-defined karyotype was not available. In this paper, a detailed karyo-morphological analysis and molecular cytogenetic studies were conducted on globe artichoke (Cynara cardunculus Linnaeus, 1753 var. scolymus Fiori, 1904) and leafy cardoon (C. cardunculus Linneaus, 1753 var. altilis De Candolle, 1838). Fluorescent In Situ Hybridization In Suspension (FISHIS) was applied to nuclei suspensions as a fast method for screening of labelling probes, before metaphase spread hybridization. Classic Fluorescent In Situ Hybridization (FISH) on slide, using repetitive telomeric and ribosomal sequences and Simple Sequence Repeats (SSRs) oligonucleotide as probes, identified homologous chromosome relationships and allowed development of molecular karyotypes for both varieties. The close phylogenetic relationship between globe artichoke and cardoon was supported by the very similar karyotypes but clear chromosomal structural variation was detected. In the light of the recent release of the globe artichoke genome sequencing, these results are relevant for future anchoring of the pseudomolecule sequence assemblies to specific chromosomes. In addition, the DNA content of the two crops has been determined by flow cytometry and a fast method for standard FISH on slide and methodological improvements for nuclei isolation are described.

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Research Article Mon, 26 Sep 2016 20:50:56 +0300
Simultaneous visualization of different genomes (J, JSt and St) in a Thinopyrum intermedium × Thinopyrum ponticum synthetic hybrid (Poaceae) and in its parental species by multicolour genomic in situ hybridization (mcGISH) https://compcytogen.pensoft.net/article/7305/ Comparative Cytogenetics 10(2): 283-293

DOI: 10.3897/CompCytogen.v10i2.7305

Authors: Klaudia Kruppa, Marta Molnar-Lang

Abstract: Multicolour genomic in situ hybridization (mcGISH) using total genomic DNA probes from Thinopyrum bessarabicum (Săvulescu & Rayss, 1923) Á. Löve, 1984 (genome Jb or Eb, 2n = 14), and Pseudoroegneria spicata (Pursh, 1814) Á. Löve, 1980 (genome St, 2n = 14) was used to characterize the mitotic metaphase chromosomes of a synthetic hybrid of Thinopyrum intermedium (Host, 1805) Barkworth & D.R. Dewey, 1985 and Thinopyrum ponticum (Podpěra, 1902) Z.-W. Liu et R.-C.Wang, 1993 named „Agropyron glael” and produced by N.V. Tsitsin in the former Soviet Union. The mcGISH pattern of this synthetic hybrid was compared to its parental wheatgrass species. Hexaploid Th. intermedium contained 19 J, 9 JSt and 14 St chromosomes. The three analysed Th. ponticum accessions had different chromosome compositions: 43 J + 27 JSt (PI531737), 40 J + 30 JSt (VIR-44486) and 38 J + 32 JSt (D-3494). The synthetic hybrid carried 18 J, 28 JSt and 8 St chromosomes, including one pair of J-St translocation and/or decreased fluorescent intensity, resulting in unique hybridization patterns. Wheat line Mv9kr1 was crossed with the Thinopyrum intermedium × Thinopyrum ponticum synthetic hybrid in Hungary in order to transfer its advantageous agronomic traits (leaf rust and yellow rust resistance) into wheat. The chromosome composition of a wheat/A.glael F1 hybrid was 21 wheat + 28 wheatgrass (11 J + 14 JSt+ 3 S). In the present study, mcGISH involving the simultaneous use of St and J genomic DNA as probes provided information about the type of Thinopyrum chromosomes in a Th. intermedium/Th. ponticum synthetic hybrid called A. glael.

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Short Communication Fri, 17 Jun 2016 11:31:21 +0300
Karyological investigations and new chromosome number reports in Bellevalia Lapeyrouse, 1808 and Muscari Miller, 1758 (Asparagaceae) from Algeria https://compcytogen.pensoft.net/article/6445/ Comparative Cytogenetics 10(1): 171-187

DOI: 10.3897/CompCytogen.v10i1.6445

Authors: Nadjat Azizi, Rachid Amirouche, Nabila Amirouche

Abstract: Karyological investigations were carried out on four species of Bellevalia Lapeyrouse, 1808 and Muscari Miller, 1758 (Asparagaceae) sampled in contrasting bioclimatic conditions of Algeria. The endemic B. mauritanica Pomel, 1874 was found to have a tetraploid cytotype 2n = 4x = 16 and an octoploid 2n = 8x = 32 which is a new report. The chromosome number 2n = 2x = 18 in M. comosum (Linnaeus, 1753) Miller, 1768 and M. maritimum Desfontaines, 1798 was in conformity with earlier reports. The latter species reveals a lesser bimodality of the karyotype. Within M. neglectum Gussone ex Tenore, 1842 pentaploid (2n = 5x = 45), hexaploid (2n = 6x = 54) and very rare octoploid cytotype (2n = 8x = 72) have been reported in Algeria. Principal component analysis performed on basis of karyotype parameters, showed a segregation of the different cytotypes. This study provides new karyological information, which is discussed in a taxonomic context.

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Research Article Mon, 21 Mar 2016 11:13:01 +0200
Refinement of the karyological aspects of Psidium guineense (Swartz, 1788): a comparison with Psidium guajava (Linnaeus, 1753) https://compcytogen.pensoft.net/article/6462/ Comparative Cytogenetics 10(1): 117-128

DOI: 10.3897/CompCytogen.v10i1.6462

Authors: Anelise Marques, Amélia Carlos Tuler, Carlos Roberto Carvalho, Tatiana Carrijo, Marcia Flores da Silva Ferreira, Wellington Clarindo

Abstract: Euploidy plays an important role in the evolution and diversification of Psidium Linnaeus, 1753. However, few data about the nuclear DNA content, chromosome characterization (morphometry and class) and molecular markers have been reported for this genus. In this context, the present study aims to shed light on the genome of Psidium guineense Swartz, 1788, comparing it with Psidium guajava Linnaeus, 1753. Using flow cytometry, the nuclear 2C value of P. guineense was 2C = 1.85 picograms (pg), and the karyotype showed 2n = 4x = 44 chromosomes. Thus, P. guineense has four chromosome sets, in accordance with the basic chromosome number of Psidium (x = 11). In addition, karyomorphometric analysis revealed morphologically identical chromosome groups in the karyotype of P. guineense. The high transferability of microsatellites (98.6%) further corroborates with phylogenetic relationship between P. guajava and P. guineense. Based on the data regarding nuclear genome size, karyotype morphometry and molecular markers of P. guineense and P. guajava (2C = 0.95 pg, 2n = 2x = 22 chromosomes), P. guineense is a tetraploid species. These data reveal the role of euploidy in the diversification of the genus Psidium.

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Short Communication Tue, 2 Feb 2016 21:33:18 +0200
Screening and chromosome localization of two cotton BAC clones https://compcytogen.pensoft.net/article/5304/ Comparative Cytogenetics 10(1): 1-15

DOI: 10.3897/CompCytogen.v10i1.5304

Authors: Xinglei Cui, Fang Liu, Yuling Liu, Zhongli Zhou, Chunying Wang, Yanyan Zhao, Fei Meng, Xingxing Wang, Xiaoyan Cai, Yuhong Wang, Renhai Peng, Kunbo Wang

Abstract: Two bacterial artificial chromosome (BAC) clones (350B21 and 299N22) of Pima 90-53 cotton [Gossypium barbadense Linnaeus, 1753 (2n=4x=52)] were screened from a BAC library using SSR markers. Strong hybridization signals were detected at terminal regions of all A genome (sub-genome) chromosomes, but were almost absent in D genome (sub-genome) chromosomes with BAC clone 350B21 as the probe. The results indicate that specific sequences, which only exist at the terminal parts of A genome (sub-genome) chromosomes with a huge repeat number, may be contained in BAC clone 350B21. When utilizing FISH with the BAC clone 299N22 as probe, a pair of obvious signals was detected on chromosome 13 of D genome (sub-genome), while strong dispersed signals were detected on all A genome (sub-genome) chromosomes. The results showed that peculiar repetitive sequence, which was distributed throughout all A genome (sub-genome) chromosomes, may exist in BAC clone 299N22. The absence of the repetitive sequences, which exist in the two BAC clones, in D genome may account for the genome-size variation between A and D genomes. In addition, the microcolinearity analysis of the clone 299N22 and its homologous region on G. raimondii Ulbrich, 1932 chromosome 13 (D513) indicated that the clone 299N22 might come from A sub-genome of sea island cotton (G. barbadense), and a huge number of small deletions, illegitimate recombination, translocation and rearrangements may have occurred during the genus evolution. The two BAC clones studied here can be used as cytological markers but will be also be helpful to research in cotton genome evolution and comparative genomics.

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Research Article Fri, 22 Jan 2016 11:47:25 +0200
Karyotype and genome size in Euterpe Mart. (Arecaceae) species https://compcytogen.pensoft.net/article/5522/ Comparative Cytogenetics 10(1): 17-25

DOI: 10.3897/CompCytogen.v10i1.5522

Authors: Ludmila Cristina Oliveira, Maria do Socorro Padilha de Oliveira, Lisete Chamma Davide, Giovana Augusta Torres

Abstract: Euterpe (Martius, 1823), a genus from Central and South America, has species with high economic importance in Brazil, because of their palm heart and fruits, known as açaí berries. Breeding programs have been conducted to increase yield and establish cultivation systems to replace the extraction of wild material. These programs need basic information about the genome of these species to better explore the available genetic variability. The aim of this study was to compare E. edulis (Martius, 1824), E. oleracea (Martius, 1824) and E. precatoria (Martius, 1842), with regard to karyotype, type of interphase nucleus and nuclear DNA amount. Metaphase chromosomes and interphase nuclei from root tip meristematic cells were obtained by the squashing technique and solid stained for microscope analysis. The DNA amount was estimated by flow cytometry. There were previous reports on the chromosome number of E. edulis and E. oleracea, but chromosome morphology of these two species and the whole karyotype of E. precatoria are reported for the first time. The species have 2n=36, a number considered as a pleisomorphic feature in Arecoideae since the modern species, according to floral morphology, have the lowest chromosome number (2n=28 and 2n=30). The three Euterpe species also have the same type of interphase nuclei, classified as semi-reticulate. The species differed on karyotypic formulas, on localization of secondary constriction and genome size. The data suggest that the main forces driving Euterpe karyotype evolution were structural rearrangements, such as inversions and translocations that alter chromosome morphology, and either deletion or amplification that led to changes in chromosome size.

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Research Article Fri, 22 Jan 2016 11:46:38 +0200
The contribution of cytogenetics and flow cytometry for understanding the karyotype evolution in three Dorstenia (Linnaeus, 1753) species (Moraceae) https://compcytogen.pensoft.net/article/6719/ Comparative Cytogenetics 10(1): 97-108

DOI: 10.3897/CompCytogen.v10i1.6719

Authors: Paulo Marcos Amaral-Silva, Wellington Ronildo Clarindo, Tatiana Tavares Carrijo, Carlos Roberto Carvalho, Milene Miranda Praça-Fontes

Abstract: Chromosome morphometry and nuclear DNA content are useful data for cytotaxonomy and for understanding the evolutionary history of different taxa. However, the chromosome number is the only karyotype aspect reported for the species of Dorstenia so far. In this study, the nuclear genome size of Dorstenia arifolia (Lamarck, 1786), Dorstenia bonijesu (Carauta & C. Valente, 1983) and Dorstenia elata (Hooker, 1840) was evaluated and their karyotype morphometry accomplished, with the aim of verifying the potential of those parameters to understand evolutionary issues. Mean nuclear 2C value ranged from 2C = 3.49 picograms (pg) for D. elata to 2C = 5.47 pg for D. arifolia, a variation of ± 1.98 pg. Even though showing a marked difference in 2C value, the three species exhibited the same 2n = 32. Corroborating the flow cytometry data, differences in chromosome morphology were found among the karyotypes of the species investigated. Based on this and the only phylogeny proposed for Dorstenia thus far, structural rearrangements are related to the karyotype variations among the three species. Besides, the karyological analysis suggests a polyploid origin of the Dorstenia species studied here.

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Research Article Fri, 22 Jan 2016 10:36:49 +0200
Ribosomal DNA in diploid and polyploid Setaria (Poaceae) species: number and distribution https://compcytogen.pensoft.net/article/5456/ Comparative Cytogenetics 9(4): 645-660

DOI: 10.3897/CompCytogen.v9i4.5456

Authors: Thaís Furtado Nani, Gisele Cenzi, Daniele Lais Pereira, Lisete Chamma Davide, Vania Helena Techio

Abstract: Setaria Beauvois, 1812 is a genus of economically important forage species, including Setaria italica (Linnaeus, 1753) Beauvois, 1812 and Setaria viridis (Linnaeus, 1753) Beauvois, 1812, closely related species and considered as model systems for studies of C4 plants. However, complications and uncertainties related to taxonomy of other species of the genus are frequent due to the existence of numerous synonyms for the same species or multiple species with the same name, and overlapping of morphological characteristics. Cytogenetic studies in Setaria can be useful for taxonomic and evolutionary studies as well as for applications in breeding. Thus, this study is aimed at locating 45S and 5S rDNA sites through fluorescent in situ hybridization (FISH) in S. italica, S. viridis and Setaria sphacelata (Schumacher, 1827) Stapf, Hubbard, Moss, 1929 cultivars (cvs.) Narok and Nandi. S. italica and S. viridis have 18 chromosomes with karyotype formulas 6m + 3sm and 9m, respectively. The location of 45S and 5S rDNA for these species was in different chromosome pairs among the evaluated species. S. viridis presented a more symmetrical karyotype, strengthening the ancestral relationship with S. italica. S. sphacelata cvs. Narok and Nandi have 36 chromosomes, and karyotype formulas 11m+7sm and 16m+2sm, respectively. The 45S rDNA signals for both cultivars were also observed in distinct chromosome pairs; however chromosomes bearing 5S rDNA are conserved. Karyotypic variations found among the studied species are evidence of chromosomal rearrangements.

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Research Article Wed, 7 Oct 2015 10:40:07 +0300
Variation of karyotype and nuclear DNA content among four species of Plectranthus L’ Héritier, 1788 (Lamiaceae) from Brazil https://compcytogen.pensoft.net/article/6255/ Comparative Cytogenetics 9(4): 549-563

DOI: 10.3897/CompCytogen.v9i4.6255

Authors: Thaís Furtado Nani, Amanda Teixeira Mesquita, Fernanda de Oliveira Bustamante, Sandro Barbosa, João Vítor Calvelli Barbosa, Lisete Chamma Davide

Abstract: Plectranthus is a genus which includes species of ornamental and medicinal potential. It faces taxonomic problems due to aggregating species previously belonging to the genus Coleus, a fact that has contributed to the existence of various synonymies. The species Plectranthus amboinicus, Plectranthus barbatus, Plectranthus grandis and Plectranthus neochilus are included in this context. Some authors consider P. barbatus and P. grandis as synonyms. The present work was carried out with the aim of comparing plants of the above-mentioned species, originating from different localities in Brazil, with regards to chromosome number and karyotypic morphology, correlated to the nuclear DNA content. There was no variation in chromosome number among plants of the same species. P. amboinicus was the only species to exhibit 2n=34, whereas the others had 2n=30. No karyotypic differences were found among the plants of each species, except for P. barbatus. The plants of the Plectranthus species revealed little coincidence between chromosome pairs. The nuclear DNA content allowed grouping P. amboinicus and P. neochilus, with the highest mean values, and P. grandis and P. barbatus with the lowest ones. Differences in DNA amount among the plants were identified only for P. barbatus. These results allow the inference that the populations of P. amboinicus and P. neochilus present coincident karyotypes among their plants, and P. grandis is probably a synonym of P. barbatus.

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Research Article Tue, 8 Sep 2015 17:13:42 +0300
Identification of new cytotypes of Valeriana jatamansi Jones, 1970 (Valerianaceae) from North-Western Himalayan region of India https://compcytogen.pensoft.net/article/5883/ Comparative Cytogenetics 9(4): 499-512

DOI: 10.3897/CompCytogen.v9i4.8875

Authors: Savita Rani, Tilak Raj Sharma, Rakesh Kapila, Rakesh Kumar Chahota

Abstract: Valeriana jatamansi, a medicinally important species of the family Valerianaceae, has been cytologically studied in different geographical areas of North-Western Himalayan region of India. The tetraploid cytotype with chromosome numbers 2n=32 is in conformity with the earlier reports of the species from different parts of the world. An octoploid cytotype (2n=64) makes a new addition for the species on a worldwide basis, whereas the diploid cytotype (2n=16) is new to India have been reported for the first time in India. These cytotypes (2n=16, 32, 64) show significant variations with respect to morphology as well as geographical distribution in the Western Indian Himalayas. Further, anomalous populations have been marked with meiotic abnormalities in the form of cytomixis, chromosomal stickiness, unoriented bivalents, formation of laggards and bridges resulting in abnormal microsporogenesis, and production of heterogeneous-sized fertile pollen grains along with reduced pollen fertility.

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Research Article Fri, 7 Aug 2015 00:00:00 +0300
Karyotype analysis and visualization of 45S rRNA genes using fluorescence in situ hybridization in aroids (Araceae) https://compcytogen.pensoft.net/article/4366/ Comparative Cytogenetics 9(2): 145-160

DOI: 10.3897/CompCytogen.v9i2.4366

Authors: Prabhu Shankar Lakshmanan, Katrijn Van Laere, Tom Eeckhaut, Johan Van Huylenbroeck, Erik Van Bockstaele, Ludmila Khrustaleva

Abstract: Karyotype analysis and FISH mapping using 45S rDNA sequences on 6 economically important plant species Anthurium andraeanum Linden ex André, 1877, Monstera deliciosa Liebmann, 1849, Philodendron scandens Koch & Sello, 1853, Spathiphyllum wallisii Regel, 1877, Syngonium auritum (Linnaeus, 1759) Schott, 1829 and Zantedeschia elliottiana (Knight, 1890) Engler, 1915 within the monocotyledonous family Araceae (aroids) were performed. Chromosome numbers varied between 2n=2x=24 and 2n=2x=60 and the chromosome length varied between 15.77 µm and 1.87 µm. No correlation between chromosome numbers and genome sizes was observed for the studied genera. The chromosome formulas contained only metacentric and submetacentric chromosomes, except for Philodendron scandens in which also telocentric and subtelocentric chromosomes were observed. The highest degree of compaction was calculated for Spathiphyllum wallisii (66.49Mbp/µm). B-chromosome-like structures were observed in Anthurium andraeanum. Their measured size was 1.87 times smaller than the length of the shortest chromosome. After FISH experiments, two 45S rDNA sites were observed in 5 genera. Only in Zantedeschia elliottiana, 4 sites were seen. Our results showed clear cytogenetic differences among genera within Araceae, and are the first molecular cytogenetics report for these genera. These chromosome data and molecular cytogenetic information are useful in aroid breeding programmes, systematics and evolutionary studies.

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Research Article Mon, 11 May 2015 15:17:38 +0300
Use of laser microdissection for the construction of Humulus japonicus Siebold et Zuccarini, 1846 (Cannabaceae) sex chromosome-specific DNA library and cytogenetics analysis https://compcytogen.pensoft.net/article/4313/ Comparative Cytogenetics 8(4): 323-336

DOI: 10.3897/CompCytogen.v8i4.8473

Authors: Nickolay Yakovin, Mikhail Divashuk, Olga Razumova, Alexander Soloviev, Gennady I. Karlov

Abstract: Dioecy is relatively rare among plant species, and distinguishable sex chromosomes have been reported in few dioecious species. The multiple sex chromosome system (XX/XY1Y2) of Humulus japonicus Siebold et Zuccarini, 1846 differs from that of other members of the family Cannabaceae, in which the XX/XY chromosome system is present. Sex chromosomes of H. japonicus were isolated from meiotic chromosome spreads of males by laser microdissection with the P.A.L.M. MicroLaser system. The chromosomal DNA was directly amplified by degenerate oligonucleotide primed polymerase chain reaction (DOP-PCR). Fast fluorescence in situ hybridization (FAST-FISH) using a labeled, chromosome-specific DOP-PCR product as a probe showed preferential hybridization to sex chromosomes. In addition, the DOP-PCR product was used to construct a short-insert, H. japonicus sex chromosomes-specific DNA library. The randomly sequenced clones showed that about 12% of them have significant homology to H. lupulus and 88% to Cannabis sativa Linnaeus, 1753 sequences from GenBank database. Forty-four percent of the sequences show homology to plant retroelements. It was concluded that laser microdissection is a useful tool for isolating the DNA of sex chromosomes of H. japonicus and for the construction of chromosome-specific DNA libraries for the study of the structure and evolution of sex chromosomes. The results provide the potential for identifying unique or sex chromosome-specific sequence elements in H. japonicus and could aid in the identification of sex chromosome-specific repeat and coding regions through chromosome isolation and genome complexity reduction.

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Research Article Wed, 10 Dec 2014 00:00:00 +0200
Cytotaxonomy of two species of genus Chrysolaena H. Robinson, 1988 (Vernonieae, Asteraceae) from Northeast Paraguay https://compcytogen.pensoft.net/article/1811/ Comparative Cytogenetics 8(2): 125-137

DOI: 10.3897/compcytogen.v8i2.7209

Authors: Gisela Via do Pico, Massimiliano Dematteis

Abstract: Chromosome counts and karyotypes of two species of Chrysolaena H. Robinson 1988 are presented in this paper. Mitotic analysis revealed that both taxa have x=10, a basic chromosome number considered characteristic of the genus. The chromosome number and the karyotype of C. cristobaliana are reported for the first time, as well as a new cytotype and the karyotype of C. sceptrum. Chrysolaena cristobaliana showed heptaploid cytotype with 2n=7x=70 and a karyotype composed of 46 m + 24 sm chromosomes. On the other hand, C. sceptrum presented tetraploid cytotype with 2n=4x=40 and a karyotype with 30 m + 10 sm chromosomes. Accessory chromosomes were observed in cells of both species. The chromosome analysis showed that these species differ in the chromosome number and the total chromosome length, although they showed similar chromosome morphology and asymmetry indexes. The results support the use of chromosome data in taxonomic treatments of the American members of the tribe Vernonieae.

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Research Article Mon, 19 May 2014 00:00:00 +0300
Karyomorphometry on three polyploid species of Arum L. (Araceae, Aroideae) https://compcytogen.pensoft.net/article/1804/ Comparative Cytogenetics 8(1): 71-80

DOI: 10.3897/compcytogen.v8i1.6444

Authors: Alessio Turco, Pietro Medagli, Antonella Albano, Saverio D'Emerico

Abstract: In this study three polyploid Arum Linnaeus, 1753 species from Southern Italy were chromosomally investigated. Arum italicum Miller, 1768 was found to have 2n = 84 chromosomes and a karyotype composed of numerous asymmetric chromosomes. Arum maculatum Linnaeus, 1753 and A. apulum (Carano) P. C. Boyce, 1993 were found to have 2n = 56 chromosomes. In the examined taxa some chromosome pairs were characterized by the presence of weakly coloured Feulgen-stained segments. The karyotype morphology of A. italicum was found to be similar to that of A. maculatum, but the more asymmetrical karyotype and numerous weakly coloured Feulgen-stained segments observed in the former suggest the existence of more extensive rearrangements. In contrast, A. apulum was observed to have a symmetrical karyotype. The A1, A2 and SYi karyotype asymmetry indices are presented. The relationships between these taxa in terms of karyotype morphology and evolution are discussed.

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Research Article Tue, 11 Mar 2014 00:00:00 +0200
Cytological investigations and new chromosome number reports in yarrow (Achillea millefolium Linnaeus, 1753) accessions from Iran https://compcytogen.pensoft.net/article/1802/ Comparative Cytogenetics 7(4): 271-277

DOI: 10.3897/compcytogen.v7i4.6075

Authors: Fatemehi Afshari, Mohsen Ebrahimi, Mohammad Akbari, Mostafa Farajpour

Abstract: In this study, a new chromosome number for Iranian yarrow (Achillea millefolium L.) accessions was reported. Cytological analyses on four A. millefolium accessions, indicated that two accessions were diploids (2n=2x=18) and two tetraploids (2n=4x=36). Cluster analysis based on chromosomal characteristics and karyotype asymmetry, categorized the four accessions separated into two groups. In terms of the Stebbins’ system, the karyotype of diploid accessions grouped in 2A class. The average value of the total form percentage (TF%) in the group one (diploid accessions) and two (tetraploid accessions) were 40.85 and 41.15, respectively. The group one had the highest mean value for the symmetry index (S%=57.5). Consequently, it can be inferred that diploids belonging to the group one are the earlier evolutionary forms.

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Research Article Thu, 24 Oct 2013 00:00:00 +0300
Physical mapping of 5S and 18S ribosomal DNA in three species of Agave (Asparagales, Asparagaceae) https://compcytogen.pensoft.net/article/1798/ Comparative Cytogenetics 7(3): 191-203

DOI: 10.3897/compcytogen.v7i3.5337

Authors: Victor Manuel Gomez-Rodriguez, Benjamin Rodriguez-Garay, Guadalupe Palomino, Javier Martínez, Rodrigo Barba-Gonzalez

Abstract: Agave Linnaeus, 1753 is endemic of America and is considered one of the most important crops in Mexico due to its key role in the country’s economy. Cytogenetic analysis was carried out in A. tequilana Weber, 1902 ‘Azul’, A. cupreata Trelease et Berger, 1915 and A. angustifolia Haworth, 1812. The analysis showed that in all species the diploid chromosome number was 2n = 60, with bimodal karyotypes composed of five pairs of large chromosomes and 25 pairs of small chromosomes. Furthermore, different karyotypical formulae as well as a secondary constriction in a large chromosome pair were found in all species. Fluorescent in situ hybridization (FISH) was used for physical mapping of 5S and 18S ribosomal DNA (rDNA). All species analyzed showed that 5S rDNA was located in both arms of a small chromosome pair, while 18S rDNA was associated with the secondary constriction of a large chromosome pair. Data of FISH analysis provides new information about the position and number of rDNA loci and helps for detection of hybrids in breeding programs as well as evolutionary studies.

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Research Article Mon, 12 Aug 2013 00:00:00 +0300
Cytogenetic studies in four cultivated Amaranthus (Amaranthaceae) species https://compcytogen.pensoft.net/article/1781/ Comparative Cytogenetics 7(1): 53-61

DOI: 10.3897/compcytogen.v7i1.4276

Authors: Marisa Bonasora, Lidia Poggio, Eduardo Greizerstein

Abstract: In the present study, the chromosomes numbers were confirmed, 2n = 34 for Amaranthus cruentus Linnaeus, 1759, and 2n = 32 for A. hypochondriacus Linnaeus, 1753, A. mantegazzianus Passer, 1864, and A. caudatus Linnaeus, 1753. The distribution and variability of constitutive heterochromatin were detailed using DAPI-CMA3 banding technique. The position of the nucleolus organizer region (NOR) was observed using Ag-NOR banding (active loci) and fluorescent in situ hybridization (rDNA-FISH) in the four Amaranthus species. Variations in the amount of constitutive heterochromatin were detected both within the species and between them, with DAPI-CMA3 stain. One chromosome paira NOR was found in each studied accession, with exception of A. caudatus cv. EEA INTA Anguil. This accession presented four rDNA loci (FISH), being active two of them (Ag- banding).

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Research Article Tue, 26 Mar 2013 00:00:00 +0200
Physical mapping of 5S and 18S-5.8S-26S RNA gene families in polyploid series of Cenchrus ciliaris Linnaeus, 1771 (Poaceae) https://compcytogen.pensoft.net/article/1762/ Comparative Cytogenetics 6(3): 273-286

DOI: 10.3897/compcytogen.v6i3.3380

Authors: Amina Kharrat-Souissi, Sonja Siljak-Yakovlev, Fatima Pustahija, Mohamed Chaieb

Abstract: The Buffelgrass (Cenchrus ciliaris L., Poaceae) is one of the most important pasturage grasses due to its high productivity and good forage qualities. This species possess a high adaptability to bioclimatic constraints of arid zones and may be used for the restoration of degraded arid ecosystems. Tunisian populations present three ploidy levels (4x, 5x and 6x) with a basic chromosome number x=9. This study reported for the first time the distribution of the ribosomal genes (rRNA) for pentaploid and hexaploid cytotypes of C. ciliaris. Molecular cytogenetic study using double fluorescence in situ hybridization has shown that the two rDNA families, 5S and 18S-5.8S-26S (18S), displayed intraspecific variation in number of loci among different ploidy levels. Each ploidy level was characterized by specific number of both 5S and 18S rDNA loci (two loci in tetraploid, five in pentaploid and six in hexaploid level). For three studied cytotypes (4x, 5x and 6x) all 5S rDNA loci were localized on the subcentromeric region of chromosomes, while 18S loci were situated on the telomeric region of short chromosome arms. Data of the FISH experiments show proportional increase of ribosomal loci number during polyploidization processes.

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Research Article Mon, 20 Aug 2012 00:00:00 +0300
Sex chromosome differentiation in Humulus japonicus Siebold & Zuccarini, 1846 (Cannabaceae) revealed by fluorescence in situ hybridization of subtelomeric repeat https://compcytogen.pensoft.net/article/1765/ Comparative Cytogenetics 6(3): 239-247

DOI: 10.3897/compcytogen.v6i3.3261

Authors: Oleg Alexandrov, Mikhail Divashuk, Nikolay Yakovin, Gennady Karlov

Abstract: Humulus japonicus Siebold & Zucc (Japanese hop) is a dioecious species of the family Cannabaceae. The chromosome number is 2n = 16 = 14 + XX for females and 2n = 17 = 14 + XY1Y2 for male. To date, no fluorescence in situ hybridization (FISH) markers have been established for the identification of H. japonicus sex chromosomes. In this paper, we report a method for the mitotic and meiotic sex chromosome differentiation in H. japonicus by FISH for HJSR, a high copy subtelomeric repeat. The signal is present in the subtelomeric region of one arm of the X chromosome. We demonstrate that males have two Y chromosomes that differ in FISH signal with the HJSR probe. Indeed, the HJSR probe hybridizes to a subtelomeric region on both arms of chromosome Y1 but not of chromosome Y2. The orientation and position of pseudoautosomal regions (PAR1 and PAR2) were also determined.

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Research Article Tue, 10 Jul 2012 00:00:00 +0300
Cytogeography of the Humifusa clade of Opuntia s.s. Mill. 1754 (Cactaceae, Opuntioideae, Opuntieae): correlations with pleistocene refugia and morphological traits in a polyploid complex https://compcytogen.pensoft.net/article/1744/ Comparative Cytogenetics 6(1): 53-77

DOI: 10.3897/compcytogen.v6i1.2523

Authors: Lucas Majure, Walter Judd, Pam Soltis, Doug Soltis

Abstract: Ploidy has been well studied and used extensively in the genus Opuntia to determine species boundaries, detect evidence of hybridization, and infer evolutionary patterns. We carried out chromosome counts for all members of the Humifusa clade to ascertain whether geographic patterns are associated with differences in ploidy. We then related chromosomal data to observed morphological variability, polyploid formation, and consequently the evolutionary history of the clade. We counted chromosomes of 277 individuals from throughout the ranges of taxa included within the Humifusa clade, with emphasis placed on the widely distributed species, O. humifusa (Raf.) Raf., 1820 s.l. and O. macrorhiza Engelm., 1850 s.l. We also compiled previous counts made for species in the clade along with our new counts to plot geographic distributions of the polyploid and diploid taxa. A phylogeny using nuclear ribosomal ITS sequence data was reconstructed to determine whether ploidal variation is consistent with cladogenesis. We discovered that diploids of the Humifusa clade are restricted to the southeastern United States (U.S.), eastern Texas, and southeastern New Mexico. Polyploid members of the clade, however, are much more widely distributed, occurring as far north as the upper midwestern U.S. (e.g., Michigan, Minnesota, Wisconsin). Morphological differentiation, although sometimes cryptic, is commonly observed among diploid and polyploid cytotypes, and such morphological distinctions may be useful in diagnosing possible cryptic species. Certain polyploid populations of O. humifusa s.l. and O. macrorhiza s.l., however, exhibit introgressive morphological characters, complicating species delineations. Phylogenetically, the Humifusa clade forms two subclades that are distributed, respectively, in the southeastern U.S. (including all southeastern U.S. diploids, polyploid O. abjecta Small, 1923, and polyploid O. pusilla (Haw.) Haw., 1812) and the southwestern U.S. (including all southwestern U.S. diploids and polyploids). In addition, tetraploid O. humifusa s.l., which occurs primarily in the eastern U.S., is resolved in the southwestern diploid clade instead of with the southeastern diploid clade that includes diploid O. humifusa s.l. Our results not only provide evidence for the polyphyletic nature of O. humifusa and O. macrorhiza, suggesting that each of these represents more than one species, but also demonstrate the high frequency of polyploidy in the Humifusa clade and the major role that genome duplication has played in the diversification of this lineage of Opuntia s.s. Our data also suggest that the southeastern and southwestern U.S. may represent glacial refugia for diploid members of this clade and that the clade as a whole should be considered a mature polyploid species complex. Widespread polyploids are likely derivatives of secondary contact among southeastern and southwestern diploid taxa as a result of the expansion and contraction of suitable habitat during the Pleistocene following glacial and interglacial events.

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Research Article Tue, 14 Feb 2012 00:00:00 +0200
Karyotyping and in situ chromosomal localization of rDNA sites in black cumin Bunium persicum (Boiss) B. Fedtsch,1915 (Apiaceae) https://compcytogen.pensoft.net/article/1729/ Comparative Cytogenetics 5(4): 345-353

DOI: 10.3897/compcytogen.v5i4.965

Authors: R. K. Chahota, Y. Mukai, H.K. Chaudhary, Naval Kishore, T.R. Sharma

Abstract: The fluorescent in situ hybridization (FISH) technique has been applied to somatic chromosomes in the medicinally important species, Bunium persicum, to elucidate its karyotypes. The bicolour FISH technique involving 18S-5.8S-26S and 5S ribosomal RNA genes as probes was used to assign physical localization and measurement of rDNA sites on homologous pairs of chromosomes. The two 18S-5.8S-26S rRNA gene sites were at the terminal regions of the short arms of the chromosomes 1 and 2 involving NOR region of chromosome 1. The 5S rDNA sites were found on subtelomeric region of the long arm of the chromosome number 5 and at interstitial regions of the short arm of chromosome 7. Based on direct visual analysis of chromosome length, morphology and position of FISH signals, a pioneer attempt has been made to construct metaphase karyotype in B. persicum, an endangered medicinal plant of North Western Himalayas.

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Research Article Wed, 9 Nov 2011 00:00:00 +0200
Karyological studies in ten species of Citrus (Linnaeus, 1753) (Rutaceae) of North-East India https://compcytogen.pensoft.net/article/1734/ Comparative Cytogenetics 5(4): 277-287

DOI: 10.3897/compcytogen.v5i4.1796

Authors: Marlykynti Hynniewta, Surendra Kumar Malik, Rao Rama Satyawada

Abstract: Ten Citrus (Linnaeus, 1753) species of North-East India have been karyo-morphologically analysed. All studied species had 2n=18 chromosomes without any evidence of numerical variation. All the chromosomes were found to be of metacentric and sub-metacentric in all the species; the morphology of the chromosomes showing size difference only. Symmetrical karyotype which does not have much difference in the ratio of longest to shortest chromosome in all the species was observed. Three species, C. grandis (Osbeck, 1757), C. reticulata (Blanco, 1837) and C. medica (Linnaeus, 1753) are identified as true basic species from asymmetry studies of karyotypes as they reflect on the primitive nature of their genomes. C. indica (Tanaka, 1937) occupies a special taxonomic position within the genus Citrus as a progenitor for other cultivated species

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Research Article Wed, 9 Nov 2011 00:00:00 +0200
Male meiosis, morphometric analysis and distribution pattern of 2× and 4× cytotypes of Ranunculus hirtellus Royle, 1834 (Ranunculaceae) from the cold regions of northwest Himalayas (India) https://compcytogen.pensoft.net/article/1727/ Comparative Cytogenetics 5(3): 143-161

DOI: 10.3897/compcytogen.v5i3.1359

Authors: Puneet Kumar, Vijay Singhal

Abstract: In this study, we examined the chromosome number, detailed male meiosis, microsporogenesis, pollen fertility and morphological features and distribution of 2× and 4× cytotypes of Ranunculus hirtellus Royle, 1834. The majority of the populations scored now from cold regions of the northwest Himalayas showed tetraploid (n=16) meiotic chromosome count and one of the populations studied from the Manimahesh hills existed at diploid level (n=8). The individuals of diploid cytotype exhibited perfectly normal meiotic course resulting in 100% pollen fertility and pollen grains of uniform sizes. On the other hand, the plants of the tetraploid cytotype from all the populations in spite of showing normal bivalent formation and equal distribution to the opposite poles at anaphases showed various meiotic abnormalities. The most prominent among these meiotic abnormalities was the cytomixis which involved inter PMC (pollen mother cell) chromatin material transfer at different stages of meiosis-I. The phenomenon of cytomixis induced various meiotic abnormalities which include chromatin stickiness, pycnotic chromatin, laggards and chromatin bridges, out of plate bivalents at metaphase-I, disoriented chromatin material at anaphase/telophase and micronuclei. Consequently, these populations exhibited varying percentages of pollen sterility (24 - 77 %) and pollen grains of heterogeneous sizes. Analysis of various morphometric features including the stomata in 2× and 4× cytotypes showed that increase in ploidy level in the species is correlated with gigantism of vegetative and floral characters and the two cytotypes can be distinguished from each other on the basis of morphological characters. The distribution patterns of the 2× and 4× cytotypes now detected and 2×, 3×, 4× cytotypes detected earlier by workers from other regions of the Indian Himalayas have also been discussed.

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Research Article Wed, 24 Aug 2011 00:00:00 +0300
Karyotype analysis of ten sections of Trigonella (Fabaceae) https://compcytogen.pensoft.net/article/1716/ Comparative Cytogenetics 5(2): 105-121

DOI: 10.3897/compcytogen.v5i2.969

Authors: Esra Martin, H. Akan, M. Ekici, Z. Aytac

Abstract: Karyotypes of ten sections of genus Trigonella Linnaeus, 1753 (Fabaceae) from Turkey were investigated. Somatic chromosome numbers of examined species were determined as 2n=14 and 16. The karyotype analyses of the species were carried out and somatic chromosome numbers of Trigonella plicata Boiss., 1872, T. brachycarpa (Fisch.) Moris, 1833, T. rostrata Boiss., 1872, T. lunata Boiss., 1843, T. isthmocarpa Boiss. et Balansa 1856, T. rhytidocarpa Boiss. et Balansa, 1859, T. spicata Sibth. et Sm., 1813, T. cephalotes Boiss. et Balansa 1856, T. capitata Boiss., 1843 and T. gladiata Steven, 1808 were reported for the first time. Two pairs of satellite metaphase chromosomes were observed in T. cariensis Boiss., 1843 and one pair in T. lunata. Moreover, 2 B-chromosomes were found only in T. procumbens Rchb., 1830 among all studied species. The aims of this study are to provide karyological data for a significant pool of the taxa, to show differences among them in the number, size and morphology of somatic chromosomes, to verify previous reports or represent numbers which are different from those cited previously.

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Research Article Fri, 1 Jul 2011 00:00:00 +0300
Karyotypic analysis of different populations of Carthamus tinctorius Linnaeus (Asteraceae) https://compcytogen.pensoft.net/article/1675/ Comparative Cytogenetics 3(1): 51-55

DOI: 10.3897/compcytogen.v3i1.8

Authors: Anjali Malik, A Srivastava

Abstract: Somatic chromosomes of Carthamus tinctorius L. were analysed. A karyotype formula for each studied population was formulated. Although all samples have 2n = 24, they could be differentiated by their karyotype formula and quantitative parameters of the karyotypes. The chromosomes were assorted into different categories on the basis of arms ratio following Levan et al. (1964). These were further subdivided into different types, on the basis of total length of the chromosomes. Based on an evolutionary point of view, variation in total chromosome length without major changes in the karyotype formula suggests that changes in the amounts of genomic DNA are proportional to the relative length of an each chromosome arm. All samples possessed symmetrical or slightly asymmetrical karyotype. The samples belonging to the same species were showing intra-specific or inter-specific chromosome polymorphism. This finding may provide useful information for Carthamus evolutionary, genetic, and breeding studies.

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Research Article Thu, 6 Aug 2009 00:00:00 +0300