Comparative Cytogenetics最新文献

{"title":"Chromosomal polymorphism in natural populations of <i>Chironomus</i> sp. prope <i>agilis</i> Kiknadze, Siirin, Filippova et al., 1991 (Diptera, Chironomidae).","authors":"Veronika V Golygina","doi":"10.3897/compcytogen.v16.i4.95659","DOIUrl":"https://doi.org/10.3897/compcytogen.v16.i4.95659","url":null,"abstract":"<p><p>Species Chironomussp.propeagilis Kiknadze, Siirin, Filippova et al., 1991 belongs to the <i>Ch.plumosus</i> group of sibling species. It was described on the basis of its karyotype and analysis of isozymes from one population in the Urals but since then no quantitative data on chromosomal polymorphism of this species have been published. The goal of this study is to broaden our knowledge of the chromosomal polymorphism and distribution of the Chironomussp.propeagilis, which, along with the data on chromosomal polymorphism of other species from the <i>Ch.plumosus</i> group, can give us a better understanding of the connection between chromosomal polymorphism and ecological conditions of habitats. The specimens of Chironomussp.propeagilis were found only in 8 natural populations from the Urals, Western Siberia and Kazakhstan, which allows us to conclude that the species range of Chironomussp.propeagilis is not as wide as for most other species from <i>Ch.plumosus</i> group. An analysis of chromosomal polymorphism in these 8 natural populations of Chironomussp.propeagilis has been performed. All of the studied populations were either monomorphic or showed very low level of chromosomal polymorphism, with 4.4-8.7% of heterozygous specimens per population and 0.04-0.08 heterozygotic inversion per larvae. The total number of banding sequences found in the banding sequence pool of Chironomussp.propeagilis is 10. The mapping of banding sequence p'ag2B3 is presented for the first time. Besides inversions, one reciprocal translocation was found in a population from Kazakhstan, B-chromosome was found in one population from the Urals region of Russia, and heterozygosity of the level of expression of Balbiany rings in arm G was observed in several studied populations.</p>","PeriodicalId":50656,"journal":{"name":"Comparative Cytogenetics","volume":"16 4","pages":"243-252"},"PeriodicalIF":1.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9836415/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10687552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative chromosome studies in species of subtribe Orchidinae (Orchidaceae).","authors":"Alessio Turco,&nbsp;Antonella Albano,&nbsp;Pietro Medagli,&nbsp;Robert P Wagensommer,&nbsp;Saverio D'Emerico","doi":"10.3897/compcytogen.v15.i4.75990","DOIUrl":"https://doi.org/10.3897/compcytogen.v15.i4.75990","url":null,"abstract":"Abstract In our study, FISH mapping using 18S-5.8S-25S rDNA and 5S rDNA sequences was performed for the first time on Ophrystenthredinifera Willdenow, 1805, Serapiasvomeracea (Burman f., 1770) Briquet, 1910 and Himantoglossumhircinum (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.tenthrediniferasubsp.neglecta (Parlatore, 1860) E.G. Camus, 1908 and O.tenthrediniferasubsp.grandiflora (Tenore, 1819) Kreutz, 2004 by the traditional Feulgen method and constructed the karyotype. The cytotaxonomic implications for both taxa are also discussed. In Himantoglossumhircinum, FISH and silver staining highlighted differences in the number of two rDNA families (35S and 5S) with respect to Barliarobertiana (Loiseleur-Deslongchamps, 1807) Greuter, 1967. In addition, fluorescence in situ hybridisation was also applied to diploid (2n = 2x = 36) and triploid (2n = 3x = 54) Anacamptismorio (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.","PeriodicalId":50656,"journal":{"name":"Comparative Cytogenetics","volume":"15 4","pages":"507-525"},"PeriodicalIF":1.0,"publicationDate":"2021-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8709834/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39852224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Revision of the banding sequence pool and new data on chromosomal polymorphism in natural populations of <i>Chironomusagilis</i> Shobanov et Djomin, 1988 (Diptera, Chironomidae).","authors":"Veronika V Golygina,&nbsp;Oksana V Ermolaeva","doi":"10.3897/CompCytogen.v15.i4.76761","DOIUrl":"https://doi.org/10.3897/CompCytogen.v15.i4.76761","url":null,"abstract":"<p><p>Quantitative and qualitative analysis of chromosomal polymorphism in 19 natural populations of <i>Ch.agilis</i> had been performed. Most studied populations showed a medium level of chromosomal polymorphism: on average 45±3.0% of specimens are heterozygotes with 0.52±0.01 heterozygotic inversion per larvae. Besides inversions, B-chromosomes were found in two populations. The total number of banding sequences found in banding sequence pool of <i>Ch.agilis</i> is 16. Three banding sequences - p'agiB3, p'agiD3, p'agiF3 - are described for the first time.</p>","PeriodicalId":50656,"journal":{"name":"Comparative Cytogenetics","volume":"15 4","pages":"527-541"},"PeriodicalIF":1.0,"publicationDate":"2021-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8709836/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39852225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A rare chromosomal polymorphism in a Kangayam bull (<i>Bosindicus</i>) of south India.","authors":"Vemula Harshini,&nbsp;P Kumarasamy,&nbsp;S M K Karthickeyan","doi":"10.3897/CompCytogen.v15.i4.71295","DOIUrl":"https://doi.org/10.3897/CompCytogen.v15.i4.71295","url":null,"abstract":"<p><p>A chromosomal polymorphism was detected on karyological screening of Kangayam breeding sires prior to subjecting them for frozen semen collection. One bull possessed the chromosomal complement 2n = 60, consisting of 58 acrocentric autosomes, one large sub-metacentric X-chromosome, and one small acrocentric Y-chromosome with a small visible p-arm, which was further confirmed using CBG- and GTG-banding. This polymorphism was attributed to a heterochromatin variation of the acrocentric Y-chromosome routine in the <i>Bosindicus</i> Linnaeus, 1758 cattle.</p>","PeriodicalId":50656,"journal":{"name":"Comparative Cytogenetics","volume":"15 4","pages":"459-465"},"PeriodicalIF":1.0,"publicationDate":"2021-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8695558/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39687189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A new species of the genus <i>Rhaphidosoma</i> Amyot et Serville, 1843 (Heteroptera, Reduviidae), with data on its chromosome complement.","authors":"Dmitry A Gapon,&nbsp;Valentina G Kuznetsova,&nbsp;Anna Maryańska-Nadachowska","doi":"10.3897/CompCytogen.v15.i4.78718","DOIUrl":"https://doi.org/10.3897/CompCytogen.v15.i4.78718","url":null,"abstract":"<p><p>A new species, <i>Rhaphidosomapaganicum</i> <b>sp. nov.</b> (Heteroptera: Reduviidae: Harpactorinae: Rhaphidosomatini), is described from the Dry Zone of Myanmar. It is the fifth species of <i>Rhaphidosoma</i> Amyot et Serville, 1843, known from the Oriental Region, and the first record of the genus for Myanmar and Indochina. The structure of the external and internal terminalia of the male and female is described and illustrated in detail. The completely inflated endosoma is described for the first time in reduviids. The complex structure of the ductus seminis is shown; it terminates with a voluminous seminal chamber which opens with a wide secondary gonopore and may be a place where spermatophores are formed. The new species is compared with all congeners from the Oriental Region and Western Asia. It is characterised by the absence of distinct tubercles on the abdominal tergites of the male, the presence only two long tubercles and small rounded ones on the abdominal tergites VII and VI, respectively, in the female, the presence of short fore wing vestiges which are completely hidden under longer fore wing vestiges, and other characters. In addition to the morphological description, an account is given of the male karyotype and the structure of testes of <i>Rh.paganicum</i> <b>sp. nov.</b> and another species of Harpactorinae, <i>Polididusarmatissimus</i> Stål, 1859 (tribe Harpactorini). It was found that <i>Rh.paganicum</i> <b>sp. nov.</b> has a karyotype comprising 12 pairs of autosomes and a multiple sex chromosome system (2n♂=24A+X₁X₂X₃Y), whereas <i>P.armatissimus</i> has a karyotype comprising five pairs of autosomes and a simple sex chromosome system (2n♂=10A+XY). The males of these species were found to have seven and nine follicles per testis, respectively. FISH mapping of <i>18S</i> ribosomal DNA (major <i>rDNA</i>) revealed hybridisation signals on two of the four sex chromosomes (Y and one of the Xs) in <i>Rh.paganicum</i> <b>sp. nov.</b> and on the largest pair of autosomes in <i>P.armatissimus</i>. The presence of the canonical \"insect\" (TTAGG) <i>_n</i> telomeric repeat was detected in the chromosomes of both species. This is the first application of FISH in the tribe Raphidosomatini and in the genus <i>Polididus</i> Stål, 1858.</p>","PeriodicalId":50656,"journal":{"name":"Comparative Cytogenetics","volume":"15 4","pages":"467-505"},"PeriodicalIF":1.0,"publicationDate":"2021-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8695567/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39687622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Karyotype and <i>COI</i> gene sequence of <i>Chironomusheteropilicornis</i> Wülker, 1996 (Diptera, Chironomidae) from the Gydan Peninsula, Russia.","authors":"Viktor V Bolshakov,&nbsp;Alexander A Prokin,&nbsp;Sergey V Artemenko","doi":"10.3897/CompCytogen.v15i4.73135","DOIUrl":"https://doi.org/10.3897/CompCytogen.v15i4.73135","url":null,"abstract":"<p><p>The karyotype features and gene <i>COI</i> sequence of <i>Chironomusheteropilicornis</i> Wülker, 1996 from the Gydan Peninsula are presented for the first time. Nine banding sequences were determined, eight of them hpiA2, hpiB1, hpiC1, hpiC2, hpiD1, hpiE1, hpiF3 and hpiG1 were previously known from European, Georgian (South Caucasus) and Siberian populations. One new banding sequence for <i>Ch.heteropilicornis</i>, hpiB2, was found. The hpiA2 banding sequence was found in all individuals, and this is its second finding after the Georgian population (Karmokov 2019). The hpiF3 banding sequence was found only in the homozygous state. Additional B-chromosomes are absent. The genetic distances (K2P) between <i>Ch.heteropilicornis COI</i> gene sequence from Gydan Peninsula and Norway are 1.1--1.3%, and Georgia - 1.8%, much lower than the commonly accepted threshold of 3% for species of genus <i>Chironomus</i> Meigen, 1803. The phylogenetic tree for <i>COI</i> gene sequences estimated by Bayesian inference showed geographically determined clusters of Norway and Gydan and a separate lineage of the Georgian population of <i>Ch.heteropilicornis</i>. The analysis of karyotype and <i>COI</i> gene sequences shows that the population of <i>Ch.heteropilicornis</i> from the Gydan Peninsula has an intermediate position within the <i>Ch.pilicornis</i> group between Georgian, Yakutian and Norwegian populations. The position of <i>Ch.pilicornis</i> Fabricius, 1787 from Canada and Greenland on the phylogenetic tree is discussed.</p>","PeriodicalId":50656,"journal":{"name":"Comparative Cytogenetics","volume":"15 4","pages":"447-458"},"PeriodicalIF":1.0,"publicationDate":"2021-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8671704/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39771989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative cytogenetic patterns in Carangidae fishes in association with their distribution range.","authors":"Rodrigo Xavier Soares,&nbsp;Clóvis Coutinho da Motta-Neto,&nbsp;Gideão Wagner Werneck Félix da Costa,&nbsp;Marcelo de Bello Cioffi,&nbsp;Luiz Antônio Carlos Bertollo,&nbsp;Amanda Torres Borges,&nbsp;Wagner Franco Molina","doi":"10.3897/CompCytogen.v15.i4.69638","DOIUrl":"https://doi.org/10.3897/CompCytogen.v15.i4.69638","url":null,"abstract":"<p><p>Carangidae are an important and widespreaded family of pelagic predatory fishes that inhabit reef regions or open ocean areas, some species occupying a vast circumglobal distribution. Cytogenetic comparisons among representatives of its different tribes help to understand the process of karyotype divergence in marine ecosystems due to the variable migratory ability of species. In this sense, conventional cytogenetic investigations (Giemsa staining, Ag-NORs, and C-banding), GC base-specific fluorochrome staining and FISH mapping of ribosomal DNAs were performed. Four species, <i>Elagatisbipinnulata</i> (Quoy et Gaimard, 1825) and <i>Seriolarivoliana</i> (Valenciennes, 1883) (Naucratini), with circumtropical distributions, <i>Gnathanodonspeciosus</i> (Forsskål, 1775) (Carangini), widely distributed in the tropical and subtropical waters of the Indian and Pacific oceans, and <i>Trachinotuscarolinus</i> (Linnaeus, 1766) (Trachinotini), distributed along the western Atlantic Ocean, were analyzed, thus encompassing representatives of three out its four tribes. All species have diploid chromosome number 2n = 48, with karyotypes composed mainly by acrocentric chromosomes (NF = 50-56). The 18S rDNA/Ag-NORs/GC+ and 5S rDNA loci were located on chromosomes likely homeologs. Karyotypes showed a pattern considered basal for the family or with small variations in their structures, apparently due to pericentric inversions. The migratory capacity of large pelagic swimmers, in large distribution areas, likely restricts the fixation of chromosome changes in Carangidae responsible for a low level of karyotype diversification.</p>","PeriodicalId":50656,"journal":{"name":"Comparative Cytogenetics","volume":"15 4","pages":"429-445"},"PeriodicalIF":1.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8654809/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39771752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distribution of GC-rich heterochromatin and ribosomal genes in three fungus-farming ants (Myrmicinae, Attini, Attina): insights on chromosomal evolution.","authors":"Gisele Amaro Teixeira,&nbsp;Luísa Antônia Campos Barros,&nbsp;Hilton Jeferson Alves Cardoso de Aguiar,&nbsp;Denilce Meneses Lopes","doi":"10.3897/compcytogen.v15.i4.73769","DOIUrl":"https://doi.org/10.3897/compcytogen.v15.i4.73769","url":null,"abstract":"<p><p>Cytogenetic studies on fungus-farming ants have shown remarkable karyotype diversity, suggesting different chromosomal rearrangements involved in karyotype evolution in some genera. A notable cytogenetic characteristic in this ant group is the presence of GC-rich heterochromatin in the karyotypes of some ancient and derivative species. It was hypothesized that this GC-rich heterochromatin may have a common origin in fungus-farming ants, and the increase in species studied is important for understanding this question. In addition, many genera within the subtribe Attina have few or no cytogenetically studied species; therefore, the processes that shaped their chromosomal evolution remain obscure. Thus, in this study, we karyotyped, through classical and molecular cytogenetic techniques, the fungus-farming ants <i>Cyphomyrmextransversus</i> Emery, 1894, <i>Sericomyrmexmaravalhas</i> Ješovnik et Schultz, 2017, and <i>Mycetomoelleriusrelictus</i> (Borgmeier, 1934), to provide insights into the chromosomal evolution in these genera and to investigate the presence the GC-rich heterochromatin in these species. <i>Cyphomyrmextransversus</i> (2n = 18, 10m + 2sm + 6a) and <i>S.maravalhas</i> (2n = 48, 28m + 20sm) showed karyotypes distinct from other species from their genera. <i>Mycetomoelleriusrelictus</i> (2n = 20, 20m) presented the same karyotype as the colonies previously studied. Notably, <i>C.transversus</i> presented the lowest chromosomal number for the genus and a distinct karyotype from the other two previously observed for this species, showing the existence of a possible species complex and the need for its taxonomic revision. Chromosomal banding data revealed GC-rich heterochromatin in all three species, which increased the number of genera with this characteristic, supporting the hypothesis of a common origin of GC-rich heterochromatin in Attina. Although a single chromosomal pair carries rDNA genes in all studied species, the positions of these rDNA clusters varied. The rDNA genes were located in the intrachromosomal region in <i>C.transversus</i> and <i>M.relictus</i>, and in the terminal region of <i>S.maravalhas</i>. The combination of our molecular cytogenetic data and observations from previous studies corroborates that a single rDNA site located in the intrachromosomal region is a plesiomorphic condition in Attina. In addition, cytogenetic data obtained suggest centric fission events in <i>Sericomyrmex</i> Mayr, 1865, and the occurrence of inversions as the origin of the location of the ribosomal genes in <i>M.relictus</i> and <i>S.maravalhas</i>. This study provides new insights into the chromosomal evolution of fungus-farming ants.</p>","PeriodicalId":50656,"journal":{"name":"Comparative Cytogenetics","volume":"15 4","pages":"413-428"},"PeriodicalIF":1.0,"publicationDate":"2021-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8639600/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39812398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intraspecies multiple chromosomal variations including rare tandem fusion in the Russian Far Eastern endemic evoron vole <i>Alexandromysevoronensis</i> (Rodentia, Arvicolinae).","authors":"Irina V Kartavtseva,&nbsp;Irina N Sheremetyeva,&nbsp;Marina V Pavlenko","doi":"10.3897/compcytogen.v15.i4.67112","DOIUrl":"10.3897/compcytogen.v15.i4.67112","url":null,"abstract":"<p><p>The vole <i>Alexandromysevoronensis</i> (Kovalskaya et Sokolov, 1980) with its two chromosomal races, \"Evoron\" (2n = 38-41, NF = 54-59) and \"Argi\" (2n = 34, 36, 37, NF = 51-56) is the endemic vole found in the Russian Far East. For the \"Argi\" chromosomal race, individuals from two isolated populations in mountain regions were investigated here for the first time using GTG-, GTC-, NOR methods. In the area under study, 8 new karyotype variants have been registered. The karyotype with 2n = 34 has a rare tandem fusion of three autosomes: two biarmed (Mev6 and Mev7) and one acrocentric (Mev14) to form a large biarmed chromosome (Mev6/7/14), all of which reveal a heterozygous state. For <i>A.evoronensis</i>, the variation in the number of chromosomes exceeded the known estimate of 2n = 34, 36 and amounted to 2n = 34, 36, 38-41. The combination of all the variations of chromosomes for the species made it possible to describe 20 variants of the <i>A.evoronensis</i> karyotype, with 11 chromosomes being involved in multiple structural rearrangements. In the \"Evoron\" chromosomal race 4 chromosomes (Mev1, Mev4, Mev17, and Mev18) and in the \"Argi\" chromosomal race 9 chromosomes (Mev6, Mev7, Mev14, Mev13, Mev11, Mev15, Mev17, Mev18, and Mev19) were observed. Tandem and Robertsonian rearrangements (Mev17/18 and Mev17.18) were revealed in both chromosomal races \"Evoron\" and \"Argi\".</p>","PeriodicalId":50656,"journal":{"name":"Comparative Cytogenetics","volume":"15 4","pages":"393-411"},"PeriodicalIF":1.0,"publicationDate":"2021-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8629904/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39720637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High karyotypic variation in <i>Orthemis</i> Hagen, 1861 species, with insights about the neo-XY in <i>Orthemisambinigra</i> Calvert, 1909 (Libellulidae, Odonata).","authors":"Liliana M Mola,&nbsp;María Florencia Fourastié,&nbsp;Silvia Susana Agopian","doi":"10.3897/CompCytogen.v15.i4.68761","DOIUrl":"https://doi.org/10.3897/CompCytogen.v15.i4.68761","url":null,"abstract":"<p><p>The American dragonfly genus <i>Orthemis</i> Hagen, 1861 is mainly found in the Neotropical region. Seven of 28 taxonomically described species have been reported from Argentina. Chromosome studies performed on this genus showed a wide variation in chromosome number and a high frequency of the neoXY chromosomal sex-determination system, although the sexual pair was not observed in all cases. This work analyzes the spermatogenesis of <i>Orthemisdiscolor</i> (Burmeister, 1839), <i>O.nodiplaga</i> Karsch, 1891 and <i>O.ambinigra</i> Calvert, 1909 in individuals from the provinces of Misiones and Buenos Aires, Argentina. <i>Orthemisdiscolor</i> has 2n=23, n=11+X and one larger bivalent. <i>Orthemisnodiplaga</i> exhibits the largest chromosome number of the order, 2n=41, n=20+X and small chromosomes. <i>Orthemisambinigra</i> shows a reduced complement, 2n=12, n=5+neo-XY, large-sized chromosomes, and a homomorphic sex bivalent. Fusions and fragmentations are the main evolutionary mechanisms in Odonata, as well as in other organisms with holokinetic chromosomes. <i>Orthemisnodiplaga</i> would have originated by nine autosomal fragmentations from the ancestral karyotype of the genus (2n=22A+X in males). We argue that the diploid number 23 in <i>Orthemis</i> has a secondary origin from the ancestral karyotype of family Libellulidae (2n=25). The complement of <i>O.ambinigra</i> would have arisen from five autosomal fusions and the insertion of the X chromosome into a fused autosome. C-banding and DAPI/CMA₃ staining allowed the identification of the sexual bivalent, which revealed the presence of constitutive heterochromatin. We propose that the chromosome with intermediate C-staining intensity and three medial heterochromatic regions corresponds to the neo-Y and that the neo-system of this species has an ancient evolutionary origin. Moreover, we discuss on the mechanisms involved in the karyotypic evolution of this genus, the characteristics of the neo sex-determining systems and the patterns of heterochromatin distribution, quantity and base pair richness.</p>","PeriodicalId":50656,"journal":{"name":"Comparative Cytogenetics","volume":"15 4","pages":"355-374"},"PeriodicalIF":1.0,"publicationDate":"2021-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8580954/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39643911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}