[Genetic diversity of Chionomys genus (Mammalia, Arvicolinae) and comparative phylogeography of snow voles].

In the present study, the genetic polymorphism of the Chionomys genus was examined based on the sequencing of the mitochondrial cytb gene and two nuclear exons, including CHR exon 10 and BRCA1 exon 11. The distinct subdivision of the genus of snow voles into five lineages, including Ch. nivalis, Ch. gud, Ch. roberti, and Ch. aff. nivalis from Turkey, as well as Ch. aff. gud from Turkey, was demonstrated. The branching order in the trees constructed based on the data for different genes was ambiguous, which was probably the consequence of recent and rapid radiation of the major lineages from a common ancestor. However, the data of the mitochondrial and nuclear gene analyses definitely indicated that the genetic and taxonomic diversity of the Chionomys genus was higher than it was expected before. The genetic divergence of some populations was so deep that they probably deserved the statuses of independent species. Despite that the range of the European snow vole Ch. nivalis is larger and more fragmented than the Gudaur vole Ch, gud, the latter species with its relatively small range, which is limited to the Caucasian and Pontic Mountains, was characterized by a similarly expressed phylogenetic structure. At the same time, Robert's vole Ch. roberti was less structured genetically than the first two species. The data obtained supported the Near Eastern, rather than the European origin of the Chionomys genus.

[Molecular cytogenetic markers of cryptic species and hybrids of the common vole superspecies complex Microtus arvalis s. l].

Molecular markers of cryptic cytogenetical differentiation were shown in chromosomal polymorphic Pan-European model group of rodents Microtus arvalis s. l. by FISH analysis. The polytypy of 46-chromosomes karyotypes determined by the sites of interstitial telomeric sequences (ITS) and ribosomal DNA emphasizes the genetical isolation of M. arvalis s. s. and M. obscurus.

[Meiosis in gray voles of the subgenus microtus (rodentia, arvicolinae) and in their hybrids].

The results of light and electron microscopic (EM) studies of meiosis in Microtus arvalis males of the karyoform "arvalis" (2n = 46, NFa = 80), in hybrids between the chromosomal forms arvalis and obscurus (2n = 46, NFa = 68), in M. rossiaemeridionalis voles (2n = 54, NFa = 54), and in a hybrid between the species M. rossiaemeridionalis and M. kermanensis (2n = 54, NFa = 54) are presented. SC (synaptonemal complex) karyotypes of the parental forms and the hybrids were constructed on the basis of measurements of the length ofautosomal SCs revealed by the EM analysis in spermatocytes at the stage of middle pachytene. The SC karyotypes of M. arvalis and the hybrids female obscurus x male arvalis consist of 22 synaptonemal complexes of autosomal bivalents and the axial elements of the synaptonemal complexes of the sex chromosomes X and Y. The SC karyotypes of M. rossiaemeridionalis and the hybrid M. rossiaemeridionalis x M. kermanensis consist of 26 synaptonemal complexes of autosomal bivalents and a sex bivalent; they differ only in the length of the Y chromosome axis (Y chromosome in the hybrid was inherited from M. kermanensis). Asynaptic configurations of the autosomal SCs were not observed in the hybrids. The SC axial elements of the X and Y chromosomes in the parental forms and in the hybrids were located close to each other throughout pachytene, but they did not form a synaptic region. The normal synapsis in sterile hybrids (M. rossiaemeridionalis x M. kermanensis) and the behavior of the sex chromosomes in meiosis in fertile and sterile hybrids are discussed in the context of specific features of meiosis and reproductive isolation.

X-Y chromosome synapsis and recombination in 3 vole species of Asian lineage of the genus Microtus (Rodentia: Arvicolinae).

The pattern of X-Y chromosome pairing in male meiosis is an important taxonomic feature of grey voles of the genus Microtus. Asynaptic sex chromosomes have been found in the majority of species of the Palearctic phylogenetic lineage of this genus, while normal X-Y synapsis has been observed in the species of subgenus Pallasiinus belonging to the Asian phylogenetic lineage. We analyzed sex chromosome pairing and recombination in M. maximowiczii, M. mujanensis and M. fortis which also belong to the Asian phylogenetic lineage (subgenus Alexandromys). Using immunostaining for the proteins of the synaptonemal complex (SCP3) and recombination nodules (MLH1) we demonstrated that X and Y chromosomes of these species paired and recombined in a short subtelomeric region. This indicates that the sex chromosomes of these species retain an ancestral fully functional pseudoautosomal region, which has been lost or rearranged in the asynaptic species of the genus Microtus.

[Taxonomic position of Afghan vole (subgenus Blanfordimys) by sequencing the mitochondrial cytb gene].

It is rather difficult to construct a system of gray voles of the tribe Microtini by a set of morphological and karyological characters because form generation is mosaic at these organization levels. The sequence of the mitochondrial cytochrome b gene was used to study the phylogenetic relationships and taxonomic position of the Central Asian subgenus Blanfordimys. Afghan vole Microtus (Blanfordimys) afghanus and Bucharian vole M. (Blanfordimys) bucharensis clustered with Pamir vole M. (Neodon) juldaschi, which is conventionally assigned to another subgenus. The last two species proved to be significantly closer to each other than either of them was to M. (Blanfordimys) afghanus, which disagrees with the monophyletic origin accepted for Blanfordimys. The genetic distances between the species of the subgenus Blanfordmys and M. juldaschi were comparable with the distances between the sister subgenera Microtus s. str. and Sumeriomys or Pallasiinus and Alexandromys and with the basal divergence of supraspecific clades in the subgenus Terricola. It was assumed that a special Central Asian group of species exists within the tribe Microtini and includes species of the subgenus Blanfordimys and Ml juldaschi and that the subgenera Neodon and Blanfordimys should be revised.