Latest Articles from Comparative Cytogenetics Latest 6 Articles from Comparative Cytogenetics https://compcytogen.pensoft.net/ Thu, 28 Mar 2024 11:22:47 +0200 Pensoft FeedCreator https://compcytogen.pensoft.net/i/logo.jpg Latest Articles from Comparative Cytogenetics https://compcytogen.pensoft.net/ Karyotype characteristics and gene COI sequences of Chironomus bonus Shilova et Dzhvarsheishvili, 1974 (Diptera, Chironomidae) from the South Caucasus (Republic of Georgia, Paravani river) https://compcytogen.pensoft.net/article/79182/ Comparative Cytogenetics 16(1): 19-38

DOI: 10.3897/CompCytogen.v16.i1.79182

Authors: Mukhamed Kh. Karmokov

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

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Research Article Tue, 1 Mar 2022 15:30:22 +0200
Karyotype characteristics, chromosomal polymorphism and gene COI sequences of Chironomus heteropilicornis Wülker, 1996 (Diptera, Chironomidae) from the South Caucasus https://compcytogen.pensoft.net/article/35572/ Comparative Cytogenetics 13(4): 339-357

DOI: 10.3897/CompCytogen.v13i4.35572

Authors: Mukhamed Kh. Karmokov

Abstract: The study presents data on the karyotype characteristics, features of chromosomal polymorphism and the gene COI sequences of Chironomus heteropilicornis Wülker, 1996 (Diptera, Chironomidae) from the South Caucasus. We found 8 banding sequences in the Caucasian population. Overall, The Caucasian population of the species can be characterized as having a low level of polymorphism. We found one new banding sequence hpiA2 in the banding sequence pool of Ch. heteropilicornis. We observed inversion polymorphism only in the arm F. The dendrogram of genetic distances by Nei criteria (1972) shows a clear separation of the Caucasian population from populations of Siberia. At the same time, the distance between populations of Siberia and the population of South Caucasus (0.379–0.445) almost reach the mean distance (0.474 ± 0.314) between subspecies (Gunderina 2001). Due to this, we can assume that the population of South Caucasus separated from Siberian populations at the level of subspecies. Constructed on data for COI gene sequences the phylogenetic tree estimated by the Bayesian inference shows that the sequences of Ch. heteropilicornis from the South Caucasus form a separate line in the general branch of Ch. heteropilicornis sequences. At the same time, calculated K2P genetic distances between Ch. heteropilicornis sequences from Norway and Caucasus (2.0–2.2%) do not exceed the 3% threshold for the genus Chironomus.

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Research Article Thu, 31 Oct 2019 19:07:13 +0200
Karyotype characteristics and chromosomal polymorphism of Chironomus “annularius” sensu Strenzke (1959) (Diptera, Chironomidae) from the Caucasus region https://compcytogen.pensoft.net/article/25832/ Comparative Cytogenetics 12(3): 267-284

DOI: 10.3897/CompCytogen.v12i3.25832

Authors: Mukhamed Kh. Karmokov

Abstract: The study presents data on the karyotype characteristics and features of chromosomal polymorphism of Chironomus “annularius” sensu Strenzke (1959) (Diptera, Chironomidae) from three populations of the Caucasus region (South and Central Caucasus, and Eastern Ciscaucasia). We found 17 banding sequences in the Caucasian populations. We observed inversion polymorphism in almost all chromosome arms except for arm G. The genetic distances between all the studied populations of Ch. “annularius” were calculated using Nei criteria (1972). In spite of relative geographic proximity, the genetic distances between populations of the Caucasus are quite large, and they do not form a single cluster of Caucasian populations. The population of the South Caucasus goes to the European cluster, the population of the Central Caucasus goes to the Asian cluster and the population of Eastern Ciscaucasia does not belong to any of the outlined clusters. Principal component analysis (PCA) shows a similar picture. Two of the Caucasian populations do not follow Hardy-Weinberg expectation, there being a marked deficiency of heterozygotes in arms A, B and C, arguably, due to negative selection of heterozygotes or founder effect. All the obtained data are indicative of the complex genetic structure of Caucasian populations of Ch. “annularius” and total complexity microevolution processes occurring in the Caucasus region.

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Research Article Mon, 30 Jul 2018 13:57:58 +0300
Sex chromosome diversity in Armenian toad grasshoppers (Orthoptera, Acridoidea, Pamphagidae) https://compcytogen.pensoft.net/article/6407/ Comparative Cytogenetics 10(1): 45-59

DOI: 10.3897/CompCytogen.v10i1.6407

Authors: Alexander G. Bugrov, Ilyas E. Jetybayev, Gayane H. Karagyan, Nicolay B. Rubtsov

Abstract: Although previous cytogenetic analysis of Pamphagidae grasshoppers pointed to considerable karyotype uniformity among most of the species in the family, our study of species from Armenia has discovered other, previously unknown karyotypes, differing from the standard for Pamphagidae mainly in having unusual sets of sex chromosomes. Asiotmethis turritus (Fischer von Waldheim, 1833), Paranocaracris rubripes (Fischer von Waldheim, 1846), and Nocaracris cyanipes (Fischer von Waldheim, 1846) were found to have the karyotype 2n♂=16+neo-XY and 2n♀=16+neo-XX, the neo-X chromosome being the result of centromeric fusion of an ancient acrocentric X chromosome and a large acrocentric autosome. The karyotype of Paranothrotes opacus (Brunner von Wattenwyl, 1882) was found to be 2n♂=14+X1X2Y and 2n♀=14+X1X1X2X2., the result of an additional chromosome rearrangement involving translocation of the neo-Y and another large autosome. Furthermore, evolution of the sex chromosomes in these species has involved different variants of heterochromatinization and miniaturization of the neo-Y. The karyotype of Eremopeza festiva (Saussure, 1884), in turn, appeared to have the standard sex determination system described earlier for Pamphagidae grasshoppers, 2n♂=18+X0 and 2n♀=18+XX, but all the chromosomes of this species were found to have small second C-positive arms. Using fluorescent in situ hybridization (FISH) with 18S rDNA and telomeric (TTAGG)n DNA repeats to yield new data on the structural organization of chromosomes in the species studied, we found that for most of them, clusters of repeats homologous to 18S rDNA localize on two, three or four pairs of autosomes and on the X. In E. festiva, however, FISH with labelled 18S rDNA painted C-positive regions of all autosomes and the X chromosome; clusters of telomeric repeats localized primarily on the ends of the chromosome arms. Overall, we conclude that the different stages of neo-Y degradation revealed in the Pamphagidae species studied make the family a very promising and useful model for studying sex chromosome evolution.

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Research Article Fri, 22 Jan 2016 12:43:43 +0200
Karyotype characteristics and polymorphism peculiarities of Chironomus bernensis Wülker & Klötzli, 1973 (Diptera, Chironomidae) from the Central Caucasus and Ciscaucasia https://compcytogen.pensoft.net/article/4519/ Comparative Cytogenetics 9(3): 281-297

DOI: 10.3897/CompCytogen.v9i3.4519

Authors: Mukhamed Kh. Karmokov, Natalia V. Polukonova, Olga V. Sinishkina

Abstract: Data about the karyotype characteristics, features of chromosomal polymorphism and larval morphology of populations of Chironomus bernensis Wülker & Klötzli, 1973 (Diptera, Chironomidae) from the Central Caucasus (the northern macroslope) and Ciscaucasia are presented. The characteristics of the pericentromeric regions of the long chromosomes of this species from Caucasian populations were very similar to the ones from some European populations (from Poland and Italy), but differed from Swiss and Siberian populations. In the North Caucasian populations 10 banding sequences were found: two in arms A, C, and E, and one in arms B, D, F, and G. Nine of them were already known for this species, and one, berC2, is described for the first time. Cytogenetic distances between all the studied populations of Ch. bernensis show that close geographical location of all studied populations from the Central Caucasus and Ciscaucasia is reflected in their similar cytogenetic structure, but on the other hand, that they are more closely related to populations from Europe than to populations from Western Siberia. At the same time, all studied larvae from Caucasian populations have a four-bladed premandible, instead of a two-bladed one, as in the description of Ch. bernensis from Switzerland (Wülker and Klötzli 1973, Polukonova 2005c). These peculiarities may indicate the relative isolation of the Caucasus from the viewpoint of microevolution. Further research on karyological and morphological characteristics of Chironomus bernensis from geographically distant regions is necessary as there is a possibility that the presently known species is actually polytypic and consists of several sibling species.

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Research Article Tue, 23 Jun 2015 08:56:42 +0300
Chromosomal and molecular evidence for presence of Polyommatus (Agrodiaetus) poseidon (Lepidoptera, Lycaenidae) in Caucasus region https://compcytogen.pensoft.net/article/5020/ Comparative Cytogenetics 9(2): 249-255

DOI: 10.3897/CompCytogen.v9i2.5020

Authors: Vladimir A. Lukhtanov, Valentin V. Tikhonov

Abstract: We show how combination of chromosomal and molecular markers can be applied for proper species identification in Agrodiaetus Hübner, 1822 blue butterflies. Using this approach we provide first evidence for presence of P. (A.) poseidon (Herrich-Schäffer, [1851]) in Georgia.

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Short Communication Wed, 3 Jun 2015 11:31:25 +0300