Location via proxy:   [ UP ]  
[Report a bug]   [Manage cookies]                
Skip to main content
Closely related mammalian species often have differences in chromosome number and morphology, but there is still a debate about how these differences relate to reproductive isolation. To study the role of chromosome rearrangements in... more
Closely related mammalian species often have differences in chromosome number and morphology, but there is still a debate about how these differences relate to reproductive isolation. To study the role of chromosome rearrangements in speciation, we used the gray voles in the Alexandromys genus as a model. These voles have a high level of chromosome polymorphism and substantial karyotypic divergence. We investigated testis histology and meiotic chromosome behavior in the captive-bred colonies of Alexandromys maximowiczii, Alexandromys mujanensis, two chromosome races of Alexandromys evoronensis, and their interracial and interspecies hybrids, to explore the relationship between karyotypic differences and male hybrid sterility. We found that the seminiferous tubules of the males of the parental species and the interracial hybrids, which were simple heterozygotes for one or more chromosome rearrangements, contained germ cells at all stages of spermatogenesis, indicating their potential...
The Chinese hamster (Cricetulus griseus) and striped hamster (Cricetulus barabensis) are very closely related species with similar karyotypes. The karyotypes differ from each other by one Robertsonian rearrangement and X-chromosome... more
The Chinese hamster (Cricetulus griseus) and striped hamster (Cricetulus barabensis) are very closely related species with similar karyotypes. The karyotypes differ from each other by one Robertsonian rearrangement and X-chromosome morphology. The level of the tandem repeat (TR) sequences’ evolutional variability is high. The aim of the current work was to trace the TR distribution on the chromosomes of two very closely related species. The striped hamster genome has not yet been sequenced. We classified the Chinese hamster TR in the assemblies available and then compared the mode of the TR distribution in closely related species. Chinese and striped hamsters are separate species due to the relative species specificity of Chinese hamster TR and prominent differences in the TR distribution in both species. The TR variation observed within homologous striped hamster chromosomes is caused by a lack of inbreeding in natural populations. The set of TR tested could be used to examine the ...
The vole Alexandromys evoronensis (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”... more
The vole Alexandromys evoronensis (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 A. evoronensis, 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 A. evoronensis karyotype, with 11 chromosomes being involv...
Abstract On the basis of a study of our own and published data on voles from the shores of Lake Evoron ( n  = 8) and the Amgun River ( n = 8) in the Evoron-Chukchagir lowland, as well as individuals from laboratory breeding, new data on... more
Abstract On the basis of a study of our own and published data on voles from the shores of Lake Evoron ( n  = 8) and the Amgun River ( n = 8) in the Evoron-Chukchagir lowland, as well as individuals from laboratory breeding, new data on karyotypic variation (2 n = 38–41, NF = 54–59), chromosomal transformations, and their combinations in the karyotype are presented. The numbering of chromosomes in the Evoron vole karyotype using differential (GTG) staining methods made it possible to identify pairs of chromosomes involved in various chromosomal rearrangements and to number the original pairs for the pairs formed from them by chromosome fusion. The tandem telomere-telomere (TTel) fusions of biarmed chromosomes form a large submetacentric element Mev1/4M; telomere-centromere fusion (TCen) as a result of inactivation of the centromere in one of the acrocentric pairs forms either an acrocentric (Mev17/18A) or metacentric element (Mev17/18M), and the Robertsonian translocation of the same pairs forms a metacentric element (Mev17/18M). The variability of the centromere position in two pairs of autosomes (Mev8 and Mev14) is also shown. The revealed rearrangements made it possible to describe twelve variants of the karyotype: two with 2 n = 41, six with 2 n = 40, three with 2 n = 39, and one with 2 n = 38. It is proposed that the voles of the Evoron-Chukchagir lowland be assigned to the “еvoron” chromosome race, and the other voles be assigned to the “argi” race. Prolific offspring from the individuals with TTel fusion in the karyotype and a high percentage of this rearrangement in individuals from natural sample sets indicates the absence of a harmful effect on the viability of voles.
The DNA-barcoding and chromosomal study of the eastern water bat, Myotis petax Hollister, 1912, from the earlier unexplored localities in the Russian Far East are carried out. The COI barcoding obtained for 18 from a total of 19... more
The DNA-barcoding and chromosomal study of the eastern water bat, Myotis petax Hollister, 1912, from the earlier unexplored localities in the Russian Far East are carried out. The COI barcoding obtained for 18 from a total of 19 individuals captured in five localities in the Russian Far East showed the low nucleotide variability with the prevalence of the central, the most abundant haplotype. The chromosomal characteristics of eight M. petax specimens (2n = 44, NFa = 52) in the Russian Far East are clarified. The number and localization of NOR in karyotype of M. petax is described at the first time and differ from distributional patterns of NOR in the sibling species M. daubentonii Kuhl, 1819 that can be used as diagnostic feature. The considerable intraspecific variability in the distribution of heterochromatin material revealed is not typical of the genus Myotis, but it has been found in other species of the family Vespertilionidae.
The Muya Valley vole (Microtus mujanensis) has a constant diploid chromosome number of 2n = 38, but an unstable karyotype with polymorphic chromosome pairs. Here, we describe 4 karyotypic variants involving 2 polymorphic chromosome pairs,... more
The Muya Valley vole (Microtus mujanensis) has a constant diploid chromosome number of 2n = 38, but an unstable karyotype with polymorphic chromosome pairs. Here, we describe 4 karyotypic variants involving 2 polymorphic chromosome pairs, MMUJ8 and MMUJ14, in 6 animals from Buryatia using a combination of GTG-banding and chromosome painting with M. agrestis probes. We suggest that the polymorphic pairs MMUJ8 and MMUJ14 were formed through pericentric inversions that played a major role during karyotype evolution of the species. We also propose that the stable diploid number with some ongoing polymorphism in the number of chromosome arms indicates that this evolutionarily young endemic species of Russian Far East is on the way to karyotype and likely species stabilization.
Distribution of nucleolus organizer regions (NORs) in karyotypes was studied in 10 species of wood mice, including Apodemus flavicollis, A. sylvaticus, A. uralensis (= A. microps), A. fulvipectus (= A. falzfeini), A. ponticus, A.... more
Distribution of nucleolus organizer regions (NORs) in karyotypes was studied in 10 species of wood mice, including Apodemus flavicollis, A. sylvaticus, A. uralensis (= A. microps), A. fulvipectus (= A. falzfeini), A. ponticus, A. hyrcanicus, A. mystacinus, A. agrarius, A. peninsulae, and A. speciosus. Peculiarities of NOR location in karyotypes can be used in interspecific diagnostics of wood mice. Intraspecific polymorphism of A. sylvaticus, A. agrarius, and A. peninsulae in terms of the number of NORs and their localization in chromosomes can serve as evidence for karyological differentiation in certain populations of these species. The minimum number of active NORs in mice of the genus Apodemus is two to four. Two A. flavicollis wood mice with karyotypes containing one small acrocentric B-chromosome (2n = 49) were identified among animals captured in Estonia. In A. peninsulae, B-chromosomes were found among animals captured in the following regions: the vicinity of Kyzyl (one mouse with 17 microchromosomes, 2n = 65); the vicinity of Birakan (two mice with one metacentric chromosome each, 2n = 49); and in the Ussuri Nature Reserve (one mouse with five B-chromosomes, including three metacentric and two dotlike chromosomes; 2n = 65). In the latter animal, the presence of NORs on two metacentric B-chromosomes was revealed; this is the first case of identification of active NORs on extra chromosomes of mammals.
... Abstract, Distribution of nucleolus organizer regions (NORs) in karyotypes was studied in 10 species of wood mice, including Apodemus flavicollis, A. sylvaticus, A. uralensis (=A. microps), A. fulvipectus (=A. falzfeini), A. ponticus,... more
... Abstract, Distribution of nucleolus organizer regions (NORs) in karyotypes was studied in 10 species of wood mice, including Apodemus flavicollis, A. sylvaticus, A. uralensis (=A. microps), A. fulvipectus (=A. falzfeini), A. ponticus, A. hyrcanicus, A. mystacinus, A. agrarius, A ...
Data on the complex genetic analysis of three sympatric species of Caucasian wood mice, Apodemus ponticus, A. fulvipectus, and A. uralensis are presented. A high degree of genetic differentiation at the isozymic, karyological and... more
Data on the complex genetic analysis of three sympatric species of Caucasian wood mice, Apodemus ponticus, A. fulvipectus, and A. uralensis are presented. A high degree of genetic differentiation at the isozymic, karyological and molecular (nuclear DNA) levels was revealed. The genetic distances between each pair of species varied significantly within a wide range depending on the analyzed level of the organization of genetic material. Mean values of genetic divergence from one species to another were also variable. These findings indicated that evolution of chromosomes was slower than that of isozymes, and the degree of species divergence was similar on cytogenetic and molecular levels. They also suggested that the rates of species evolution could vary in different phyletic lineages and on different levels of organization. Some phyletic lineages of Apodemus could be distinguished by different directions of evolution.
G-banding and C-banding of chromosomes were studied in populations of the red-backed mouse Clethrionomys rufocanus from 11 localities of eastern Russia. Intrapopulation polymorphism of autosome 3 caused by the deletion-duplication of the... more
G-banding and C-banding of chromosomes were studied in populations of the red-backed mouse Clethrionomys rufocanus from 11 localities of eastern Russia. Intrapopulation polymorphism of autosome 3 caused by the deletion-duplication of the short-arm heterochromatin (2n = 56; NFa = 56-58) was demonstrated. The karyotype of Cl. rufocanus from continental populations and Sakhalin Island was shown to have a large subtelocentric chromosome of pair 3 (NFa = 58), whereas in the population from Kunashir Island, chromosomes of this pair were acrocentric (NFa = 56). One animal from the population of the Kedrovaya Pad' Reserve (Primorsk krai) had a pericentric inversion (acrocentric morphology) of the Y chromosome. In two animals, a female from the Ussuriiskii Reserve (Primorsk krai) and a male captured near the Tomari Settlement (Sakhalin Island), a pericentric inversion of one chromosome of pair 6 was found (NFa = 59). The inversion detected in the animal from the Sakhalin population was accompanied by the loss of the centromeric heterochromatin. In contrast, the inversion of the chromosome pair 6, which was found in the mouse from the Primorsk krai population, did not involve the loss of centromeric heterochromatin. Analysis of our results and data from the literature showed that the karyotype of Cl. rufocanus is not constant, as was thought earlier. The percentage of animals with abnormal karyotype (1.6%) was higher than in other groups of red-backed mice studied (0.12-0.7%).
Electrophoretic analysis of 12 enzyme systems and 3 nonenzyme proteins (in all, 24 interpretable loci) was carried out for Microtus oeconomus from ten Kuril islands, Kamchatka Peninsula, and the vicinity of the city of Magadan. Gene... more
Electrophoretic analysis of 12 enzyme systems and 3 nonenzyme proteins (in all, 24 interpretable loci) was carried out for Microtus oeconomus from ten Kuril islands, Kamchatka Peninsula, and the vicinity of the city of Magadan. Gene geographic variation was examined and the coefficients of genetic variation and differentiation were estimated. The inter-population allozyme differentiation was low (DNEI, 1972 not higher than 0.053) and caused by variation in the allele frequencies of polymorphic loci. The greatest genetic distances were found between the populations belonging to different subspecies. Allozyme differentiation of Far Eastern M. oeconomus and M. fortis are discussed in relation to the data on the age of the island isolation and paleontological records. Karyological analysis (G-, C-, and NOR-banding) demonstrated the absence of differences between M. oeconomus from Kamchatka and the vicinity of Magadan.
Apodemus peninsulae is a field mouse that inhabits the broad-leafed forests of temperate Eurasia. We examined the mitochondrial cytochrome b gene in 57 in dividuals of A. peninsulae from northeastern Asia, including Siberia, Primorye,... more
Apodemus peninsulae is a field mouse that inhabits the broad-leafed forests of temperate Eurasia. We examined the mitochondrial cytochrome b gene in 57 in dividuals of A. peninsulae from northeastern Asia, including Siberia, Primorye, Magadan region, Sakhalin, Hokkaido, and the Korean Peninsula. The genealogy of the mitochondrial DNA (mtDNA) in A. peninsulae was shown to have substantial geographic affinity, suggesting geographic architecture of northeastern Asia, including the islands of Sakhalin and Hokkaido, played important roles on the cladogenesis. Taking into account the presence of region-specific anciently divergent mtDNA types, three parts of the regions of Primorye, Siberia, and the Korean Peninsula can be denoted as refugia for A. peninsulae during the substantial period of the Quaternary glacial ages. Among the geographic regions examined, Primorye is likely to be the most influential one, from which the mtDNA is thought to have migrated to the neighboring regions of Sa...
Genetic diversity of Siberian roe deer Capreolus pygargus, 1771 from the Russian Far East was studied based on polymorphism analysis of a mtDNA control region fragment (390 bp). Three phylogenetic lines were found in the animals examined.... more
Genetic diversity of Siberian roe deer Capreolus pygargus, 1771 from the Russian Far East was studied based on polymorphism analysis of a mtDNA control region fragment (390 bp). Three phylogenetic lines were found in the animals examined. The trend for change of haplotypes of different phylogroups was shown to occur from north to south in Sikhote-Alin. The haplotype distribution of Siberian roe deer in the Russian Far East correlated with data on morphologiocal variability.
The homology of DNA of C-positive centromeric regions of chromosomes in wood mice of the genus Sylvaemus (S. uralensis, S. fulvipectus, S. sylvaticus, S. flavicollis, and S. ponticus) was estimated for the first time. DNA probes were... more
The homology of DNA of C-positive centromeric regions of chromosomes in wood mice of the genus Sylvaemus (S. uralensis, S. fulvipectus, S. sylvaticus, S. flavicollis, and S. ponticus) was estimated for the first time. DNA probes were generated by microdissection from the centromeric regions of individual autosomes of each species, and their fluorescence in situ hybridization (FISH) with metaphase chromosomes of representatives of all studied wood mouse species was carried out. Unlike in the chromosomal forms and races of S. uralensis, changes in the DNA composition of the chromosomal centromeric regions in the wood mouse species of the genus Sylvaemus (including closely related S. flavicollis and S. ponticus) are both quantitative and qualitative. The patterns of FISH signals after in situ hybridization of the microdissection DNA probes with chromosomes of the species involved in the study demonstrate significant differences between C-positive regions of wood mouse chromosomes in the copy number and the level of homology of repetitive sequences as well as in the localization of homologous repetitive sequences. It was shown that C-positive regions of wood mouse chromosomes can contain both homologous and distinct sets of repetitive sequences. Regions enriched with homologous repeats were detected either directly in C-positive regions of individual chromosomes or only on the short arms of acrocentrics, or at the boundary of C-positive and C-negative regions.