M. V. Pavlenko

A spatial aspect on mitochondrial DNA genealogy in Apodemus peninsulae from East Asia.

Apodemus peninsulae is a field mouse that inhabits the broad-leafed forests of temperate Eurasia. We examined the mitochondrial cytochrome b gene in 57 individuals 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 Sakhalin, Hokkaido, the Magadan region, and Siberia during the evolution of this species.

Gene-Geographic Variation and Genetic Differentiation in Red-Backed Voles of the Genus Clethrionomys (Rodentia, Cricetidae) from the Region of the Sea of Okhotsk

Thirteen enzyme systems and three nonenzyme proteins were electrophoretically analyzed in red-backed voles of the genus Clethrionomys. In total, 25 loci were interpreted. Gene-geographic variation was studied and indices of genetic variability and differentiation were determined. By the distribution of electrophoretic variants of hemoglobin, C. rutilus was shown to be divided into two geographical groups (northern and southern). A low level of genetic differentiation was revealed in the island isolates of C. rutilus and C. rufocanus. Separation of C. rufocanus, C. rex, and C. sicotanensisinto a superspecies complex was confirmed. A study of differential G- and C-banding on C. rutilus andC. rufocanus chromosomes did not reveal intraspecific variation of autosomes. In these species, karyotypes of voles from Kamchatka Peninsula were studied for the first time. They appeared to be morphologically similar to the karyotypes continental voles by both autosomes and sex chromosomes.

Features of the B chromosome in Korean field mouse Apodemus peninsulae (Thomas, 1906) from Transbaikalia and the Far East identified by the FISH method

Korean field mouse (Apodemus peninsulae) is widely distributed throughout northeastern Asia, including the Russian Far East, northern China, the Korean Peninsula, Sakhalin, and Hokkaido. This mouse species is characterized by a high frequency of animals with B chromosomes differing in their number, morphology, and DNA composition in different geographical regions. For the first time a comparative analysis of DNA probes from B chromosomes with metaphase chromosomes of mice from Transbaikalia, the Far East (including the Russian Far East), Japan, and South Korea was conducted by in situ hybridization. B chromosomes in mice from the Russian Far East were shown to exhibit low variability in DNA content; however, the DNA composition of B chromosomes in species from Transbaikalia and Japan were highly variable. B chromosomes in A. peninsulae from the South Korean population demonstrate minor differences from those from the Russian Far East. We discuss the origin of B chromosomes in the studied region in comparison with previously obtained data for mice from Siberia and the Baikal region, as well as the dispersal routes of the Korean field mouse.

[Genetic diversity and phylogenetic relationships in the zokor subfamily Myospalacinae (Rodentia, Muridae) inferred from RAPD-PCR].

Zokors (Myospalacinae) is a group of rodents specialized for underground life, endemics of eastern Asia, which is taxonomically and evolutionarily poorly studied. We examined genetic diversity and phylogenetic relationships among zokors (Myospalax myospalax, Myospalax aspalax, Myospalax armandii, Myospalax psilurus, Myospalax smithii) using RAPD-PCR. The subfamily Myospalacinae was shown to be monophyletic and contain four evolutionary branches: M. myospalax, M. aspalax-M. armandii, M. smithii and M. psilurus. Genetic differences and high differentiation were found among the species and between two geographic forms of Manchurian zokor M. psilurus from the marginal parts of the range, Transbaikalia and Primorye. The psiluris phylogroup was shown to be dichotomically divided into two clades according to the geographical distribution of animals from Transbaikalia and Primorye. The genetic differentiation between the geographic forms of M. psilurus corresponded to the differentiation between morphologically similar species M. aspalax and M. armandii. M. armandii is a sister taxon with regard to M. aspalax. This new evidence on the evolutionary relationships among zokors does not contradict the traditional views inferred from morphological, karyological, and allozyme data, on apartness of M. myospalax and the character of evolution in this group. The species status of Myospalax psilurus Milne-Edwards, 1874, M. epsilanus Thomas, 1912, and M. armandii Milne-Edwards, 1867, which had been suggested earlier on the basis of biochemical and karyological data, was confirmed.

Diversity of the Mitochondrial DNA Cytochrome b Gene of the Field Mouse Apodemus agrarius Pallas, 1771 in the South of the Russian Far East

We studied the variability of a fragment of the cytochrome b gene and the corresponding amino acid sequence of the field mouse Apodemus agrarius (Pallas, 1771) in the South of Primorskii krai (Far East of Russia). A significant polymorphism of these traits was detected. High indices of molecular diversity were obtained. The topology of the phylogenetic tree and the median networks suggest that the population of field mice in the south of Primorskii krai originated from three maternal lines. It was noted that clustering of haplotypes on a territorial basis is absent, and the field mouse population in southern Primorskii krai can be considered as one of the key points in maintaining a high genetic diversity of the species.

Genetic diversity and phylogenetic relationships of the Manchurian zokor Myospalax psilurus (Rodentia, Muridae) according to RAPD-PCR analysis

AbstractsThe population structuring and low genetic diversity of the Manchurian zokor Myospalax psilurus Milne-Edwards, 1874, an East Asian endemic included in the Red List of Russia, were demonstrated. Two separate geographical groups differing in the level of their genetic diversity were found on the territory of the Primorskii krai. The subpopulation located closest to the main area of this species was determined as ancestral. A subspecies differentiation of the Primorskii krai and Transbaikal M. psilurus populations was shown, as was the monophyletic origin of M. psilurus and its high divergence from M. aspalax. The animals from northern localities are recommended for reintroduction in nature under species recovery programs in Primorskii krai.

Microsatellite loci variation and investigation of gene flow between two karyoforms of Cricetulus barabensis sensu lato (Rodentia, Cricetidae)

We examine the diversity of six microsatellite loci and partial RAG1 exon of “barabensis” and “pseudogriseus” karyoforms in Cricetulus barabensis sensu lato species complex. A total of 435 specimens from 68 localities ranging from Altai to the Far East are investigated. The results of the population structure analysis (factor analysis and NJ tree based on Nei genetic distances) support subdivision into two well-differentiated clusters corresponding to the two karyoforms. These karyoforms are also well differentiated by the level of microsatellite variability. In several “barabensis” specimens, we found microsatellite alleles that are common in “pseudogriseus” populations but are otherwise absent in “barabensis.” Most of these specimens originate from a single population in one of the zones of potential contact between karyoforms, Kharkhorin in Central Mongolia. These molecular results are consistent with previously published karyological data in suggesting that rare hybridization events between the two chromosomal races occur in nature.

Some Features of Cytogenetic Differentiation of Striped Hamsters, Cricetulus barabensis and Cricetulus pseudogriseus (Rodentia, Cricetidae)

The karyotypes of C. barabensis (2n = 20, NF = 38) and C. pseudogriseus (2n = 24, NF = 38) from different geographic regions of Russia have been studied. Differences in the karyotype structure (chromosome morphology and distribution of heterochromatin) between the two species are described. Variation in heterochromatin staining of the first two autosomal pairs in C. barabensis from different parts of its range has been revealed for the first time.

Genetic features and the putative sources of formation of isolated populations of the striped field mouse Apodemus agrarius Pallas, 1771 in Magadan oblast

The striped field mouse Apodemus agrarius is an invasive species new for Magadan oblast; however, the adaptation of the animals to the conditions of the habitats north of the Sea of Okhotsk has been successful. The full nucleotide sequence of the cytochrome b (cytb) gene from the mtDNA has been determined for mice from four local populations in the region (settlements of Snezhnaya Dolina, Snezhnyi, Solnechnyi, and Talon), and five cytb-haplotypes have been detected. Phylogenetic analysis revealed the similarity of cytb nucleotide sequences in the mice from the habitats north of the Sea of Okhotsk and the conspecifics from the Far East-Chinese part of the range. The invasion of A. agrarius into Talon is likely to have started from Primorsky krai, whereas the animals captured in Snezhnaya Dolina had ancestors from both Primorsky krai and from China, and the animals captured in Snezhnyi and Solnechnyi were exclusively of Chinese ancestry. The striped field mice from Snezhnyi and Solnechnyi were of a single monophyletic origin. The origin of mice captured in Snezhnaya Dolina was apparently polyphyletic, and the origin of the animals from Talon was monophyletic and different from the origin of other populations of the enclave located north of the Sea of Okhotsk. Investigation of 16 allozyme loci revealed highly significant differences between the samples of striped field mice of Snezhnyi, Solnechnyi, and Talon. The variability parameters in the set of biochemical gene markers used for the analysis showed a trend to a decrease in striped field mouse samples from the habitats north of the Sea of Okhotsk. Genetic analysis revealed that the local settlements of A. agrarius in Magadan oblast are currently represented by small isolated populations.

Genetic variability of the peripheral population of the greater long-tailed hamster Tscherskia triton (De Winton 1899) in the northeastern part of the distribution range based on sequencing data of the control region of mitochondrial DNA

The genetic variability of the greater long-tailed hamster Tscherskia triton of the peripheral population of the southern Russian Far East is evaluated compared to the central populations of China based on the nucleotide sequences of the control region of mitochondrial DNA. The high genetic diversity of the population of the southern part of Russian Far East is established, which does not confirm a hypothesis on reduction of the diversity in the peripheral populations. The presence of three phylogroups is discovered: one within Russia (“northern”) and two within China (“central” and “southern”). A deletion, absent in other taxonomically distant groups of the Old and New World and acquired by the greater long-tailed hamster over the course of its evolutionary history, is present in certain populations of this species. A preliminary hypothesis, according to which the contemporary structure of this species is determined not only by topographical and climatic events, but by human activity as well, is formulated.