RESUMEN
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.
