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Little ground squirrel (Spermophilus pygmaeus) is a polytypic species with a wide geographic range, divided by a number of large rivers (Don, Volga, and Ural rivers). Preliminary analysis of the mtDNA control region revealed substantial genetic differentiation (7%) between populations of little ground squirrel inhabiting the right and left banks of the Volga River, suggesting that large rivers act as geographic barriers for this species. Here, we present the results of the genetic diversity analysis of little ground squirrel (52 individuals from 35 localities) across the species range. The Don and Ural rivers, unlike the Volga River, had no considerable effect on the phylogeographic structure of little ground squirrel. Geographic subdivision found in ground squirrels living to the east of the Volga River could be explained by the influence of a large paleo-river flowing along the Turgai valley during glacial periods. The Volga River divides the species into two major groups (western and eastern), both with a high level of haplotype diversity. The genetic variability indices are almost twofold higher in the western clade. The results ​​of neutrality and isolation by distance tests support a relatively recent range expansion of the eastern clade. In overall, the observed structure of genetic diversity supports the hypothesis on the European origin of S. pygmaeus with the center of species origin on the territory of Caucasian geographic region. The division of little ground squirrels into western and eastern phylogenetic lineages probably occurred under the influence of fluctuations of the Caspian Sea level, due to the formation of temporary migration corridors during the regression periods.

The results of analysis of the variability of body shape of different Daphnia galeata morphs from geographically distinct populations—Lake Glubokoe (Moscow oblast) and Lake Chany (Novosibirsk oblast) are given. The morphological analysis was combined with the analysis of the variability of fragments of the 16S and 12S genes of the mitochondrial DNA (mtDNA) and the internal transcribed spacer 2 (ITS2) of the nuclear DNA. A reconstruction of the phylogenetic relationships between species of the genus Daphnia has been performed using a combined fragment of the 16S and 12S genes of the mtDNA. An inconsistency in the distribution of the 12S- and ITS2-haplotypes for the species D. galeata has been revealed, which indicates the introgression of mtDNA in the Lake Chany population.

Long-tailed ground squirrel (Urocitellus undulatus) is a polytypic species with a wide distribution from the Tien Shan to the Amur River region. Previously, considerable genetic differentiation between eastern and western populations of this species was demonstrated. Moreover, the greatest differences were observed in the western part of the range located in Central Asia, the region that was subjected to repeated glaciations in the past and represents one of the centers of the ground squirrel secondary diversification. The analysis of polymorphism of the mitochondrial DNA control region was carried out on long-tailed ground squirrels living in the northern part of Central Asia, on the territory of the Altai Mountains (45 individuals from 23 localities). The presence of two genetically differentiated (7.7% differences) and geographically separated lineages (western and eastern) was revealed. The data obtained disprove the hypothesis on unidirectional, from west to east, colonization of the Altai Mountains after the end of the last glacial maximum and show the two pathways of the ground squirrel colonization of the Altai, from both western and eastern refugia.

Variation of the cytochrome b gene fragment was examined in 27 flat-headed voles Alticola strelzowi from different parts of the species range. A total of 15 haplotypes were described, while the species is characterized by low levels of genetic differentiation and polymorphism. The haplotypes form three haplogroups, one of which corresponded to the subspecies A. s. strelzowi, and the other two, to A. s. desertorum. Based on different indices, the level of genetic polymorphism in the later subspecies was considered to be higher than in the first one. Phylogeographic analysis suggested post-glacial dispersal of flat-headed voles from a single refugium located in Western Altai. Using different techniques, relatively recent colonization of the Central Altai territory was demonstrated (subspecies A. s. strelzowi), which determined low level of genetic variation in this territory.