Latest Articles from Comparative Cytogenetics Latest 19 Articles from Comparative Cytogenetics https://compcytogen.pensoft.net/ Thu, 28 Mar 2024 19:32:58 +0200 Pensoft FeedCreator https://compcytogen.pensoft.net/i/logo.jpg Latest Articles from Comparative Cytogenetics https://compcytogen.pensoft.net/ 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
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
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
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
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
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
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
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
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
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
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
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