Latest Articles from Comparative Cytogenetics Latest 8 Articles from Comparative Cytogenetics https://compcytogen.pensoft.net/ Fri, 29 Mar 2024 16:31:31 +0200 Pensoft FeedCreator https://compcytogen.pensoft.net/i/logo.jpg Latest Articles from Comparative Cytogenetics https://compcytogen.pensoft.net/ Revision of the banding sequence pool and new data on chromosomal polymorphism in natural populations of Chironomus agilis Shobanov et Djomin, 1988 (Diptera, Chironomidae) https://compcytogen.pensoft.net/article/76761/ Comparative Cytogenetics 15(4): 527-541

DOI: 10.3897/CompCytogen.v15.i4.76761

Authors: Veronika V. Golygina, Oksana V. Ermolaeva

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

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Research Article Fri, 17 Dec 2021 09:45:09 +0200
“European” race-specific metacentrics in East Siberian common shrews (Sorex araneus): a description of two new chromosomal races, Irkutsk and Zima https://compcytogen.pensoft.net/article/19800/ Comparative Cytogenetics 11(4): 797-806

DOI: 10.3897/CompCytogen.v11i4.19800

Authors: Svetlana V. Pavlova, Sergei A. Borisov, Alexander F. Timoshenko, Boris I. Sheftel

Abstract: Karyotype studies of common shrews in the vicinity of Lake Baikal (Irkutsk Region, Eastern Siberia) resulted in the description of two new chromosomal races of Sorex araneus Linnaeus, 1758 (Lypotyphla, Mammalia), additional to 5 races formerly found in Siberia. In the karyotypes of 12 specimens from 3 locations, the polymorphism of metacentric and acrocentric chromosomes of the Robertsonian type was recorded and two distinct groups of karyotypes interpreted as the chromosomal races were revealed. They are geographically distant and described under the racial names Irkutsk (Ir) and Zima (Zi). Karyotypes of both races were characterized by species-specific (the same for all 74 races known so far) metacentric autosomes af, bc, tu and jl, and the typical sex chromosome system – XX/XY1Y2. The race-specific arm chromosome combinations include three metacentrics and four acrocentrics in the Irkutsk race (gk, hi, nq, m, o, p, r) and four metacentrics and two acrocentrics in the Zima race (gm, hi, ko, nq, p, r). Within the races, individuals with polymorphic chromosomes were detected (g/m, k/o, n/q, p/r). The presence of the specific metacentric gk allowed us to include the Irkutsk race into the Siberian Karyotypic Group (SKG), distributed in surrounding regions. The Zima race karyotype contained two metacentrics, gm and ko, which have been never found in the Siberian part of the species range, but appear as the common feature of chromosomal races belonging to the West European Karyotypic Group (WEKG). Moreover, the metacentrics of that karyotype are almost identical to the Åkarp race (except the heterozygous pair p/r) locally found in the southern Sweden. One of two Siberian races described here for the first time, the Zima race, occurs in an area considerably distant from Europe and shares the common metacentrics (gm, hi, ko) with races included in WEKG. This fact may support a hypothesis of independent formation of identical arm chromosome combinations due to occurrence of the same centric fusions in different parts of the species range.

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Research Article Fri, 24 Nov 2017 17:05:14 +0200
Study of male–mediated gene flow across a hybrid zone in the common shrew (Sorex araneus) using Y chromosome https://compcytogen.pensoft.net/article/13494/ Comparative Cytogenetics 11(2): 421-430

DOI: 10.3897/CompCytogen.v11i2.13494

Authors: Andrei V. Polyakov, Viktor V. Panov

Abstract: Despite many studies, the impact of chromosome rearrangements on gene flow between chromosome races of the common shrew (Sorex araneus Linnaeus, 1758) remains unclear. Interracial hybrids form meiotic chromosome complexes that are associated with reduced fertility. Nevertheless comprehensive investigations of autosomal and mitochondrial markers revealed weak or no barrier to gene flow between chromosomally divergent populations. In a narrow zone of contact between the Novosibirsk and Tomsk races hybrids are produced with extraordinarily complex configurations at meiosis I. Microsatellite markers have not revealed any barrier to gene flow, but the phenotypic differentiation between races is greater than may be expected if gene flow was unrestricted. To explore this contradiction we analyzed the distribution of the Y chromosome SNP markers within this hybrid zone. The Y chromosome variants in combination with race specific autosome complements allow backcrosses to be distinguished and their proportion among individuals within the hybrid zone to be evaluated. The balanced ratio of the Y variants observed among the pure race individuals as well as backcrosses reveals no male mediated barrier to gene flow. The impact of reproductive unfitness of backcrosses on gene flow is discussed as a possible mechanism of the preservation of race-specific morphology within the hybrid zone.

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Research Article Mon, 19 Jun 2017 16:12:23 +0300
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
Comparative analysis of karyotypes of Chironomus solitus Linevich & Erbaeva, 1971 and Chironomus anthracinus Zetterstedt, 1860 (Diptera, Chironomidae) from East Siberia https://compcytogen.pensoft.net/article/4702/ Comparative Cytogenetics 9(2): 237-248

DOI: 10.3897/CompCytogen.v9i2.4702

Authors: Valentina Proviz

Abstract: A comparative chromosome banding analysis of Chironomus solitus Linevich & Erbaeva, 1971 and Chironomus anthracinus Zetterstedt, 1860 from East Siberia (Lakes Baikal, Gusinoe, Arakhley and Irkutsk Reservoir) showed close similarity of banding sequences. Ch. solitus differs from Ch. anthracinus in one species-specific sequence of arm B. Arms C (43%) and D (30%) had inversion banding sequences previously reported in Ch. anthracinus The similarity of karyotypic features of Ch. solitus and Ch. anthracinus in combination with morphological features of larvae provide evidence in favour of including Ch. solitus in the C. anthracinus group of sibling species long with Ch. reservatus Shobanov, 1997.

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Research Article Wed, 3 Jun 2015 14:46:55 +0300
A comparison of the chromosome G-banding pattern in two Sorex species, S. satunini and S. araneus (Mammalia, Insectivora) https://compcytogen.pensoft.net/article/1763/ Comparative Cytogenetics 6(3): 267-271

DOI: 10.3897/compcytogen.v6i3.3019

Authors: Yuri Borisov, Victor Orlov

Abstract: The G-banded karyotype of S. satunini was compared with the karyotype of Sorex araneus. Extensive homology was revealed. The major chromosomal rearrangements involved in the evolutionary divergence of these species have been identified as centric fusions and centromeric shifts. From the known palaeontological age of S. satunini it is obvious that the vast chromosomal polymorphism of the S. araneus group originated during the middle Pleistocene.

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Research Article Mon, 20 Aug 2012 00:00:00 +0300
Presence of the 54-chromosome common vole (Mammalia) on Olkhon Island (Lake Baikal, East Siberia, Russia), and the occurrence of an unusual X-chromosome variant https://compcytogen.pensoft.net/article/1736/ Comparative Cytogenetics 5(5): 433-440

DOI: 10.3897/compcytogen.v5i5.1720

Authors: Svetlana Pavlova, A.V. Tchabovsky

Abstract: We report a new finding of the 54-chromosome sibling species of the common vole in East Siberia - the first description from Olkhon Island (Lake Baikal). The karyotype of a male specimen revealed by routine staining and C-banding demonstrates the unambiguous presence of Microtus rossiaemeridionalis Ognev, 1924 (recently often regarded as as junior synonym of M. levis Miller, 1908). Comparison with conspecific specimens from the European part of the species range (from the left bank of the river Volga) shows that the vole of the island population has a smaller X-chromosome due to a reduced quantity of C-positive heterochromatin. This is just the third example of this type of X-chromosome variant with previous cases on an Arctic island (Svalbard) and the West Siberian lowland (Novosibirsk) and the only one on a lake island. Although M. rossiaemeridionalis is largely monomorphic in its karyotype, our data show that one specific type of X-chromosome variant is remarkably widespread, though rare.

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Research Article Thu, 22 Dec 2011 00:00:00 +0200
AFLP diversity between the Novosibirsk and Tomsk chromosome races of the common shrew (Sorex araneus) https://compcytogen.pensoft.net/article/1681/ Comparative Cytogenetics 3(2): 85-89

DOI: 10.3897/compcytogen.v3i2.14

Authors: Andrey Polyakov, V Ilyashenko, S Onischenko, V Panov, P Borodin

Abstract: Genetic diversity between of the Novosibirsk and Tomsk chromosome races of the common shrew (Sorex araneus) was analyzed using 39 polymorphic AFLP (amplified fragments length polymorphism) markers. Exact and F-statistics tests for population differentiation demonstrated significant interracial difference in allele frequencies and significant subdivision between the races. The value of the genetic distance between the chromosome races observed in this study corresponds to that found between subspecies of mammals studied so far.

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Research Article Tue, 29 Dec 2009 00:00:00 +0200