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Based on the analysis of a fragment of the cytochrome b (cytb) gene of mitochondrial DNA (mtDNA), the genetic diversity of the little ground squirrel Spermophilus pygmaeus Pallas, 1779 of the Central and Eastern Caucasus was studied. Phylogenetic analysis revealed the existence of two clusters A and B within the western clade of S. pygmaeus 2. Cluster A is formed by haplotypes of ground squirrels from the Eastern Caucasus and the right bank of the Volga River, while B, only haplotypes of Central Caucasian animals. The distance between clusters A and B reaches 1.3%. The relatively isolated position on the phylogenetic tree of the ground squirrel population of the Central Caucasus, the absence of identical haplotypes in Central and Eastern Caucasian animals, and the distances obtained indicate genetic heterogeneity of the ground squirrel in the North Caucasus. The results of molecular dating showed that the evolutionary age of S. pygmaeus mtDNA haplotypes from the studied areas of the Eastern Caucasus was approximately 260 000 years, and that of the Central Caucasus, 163 000 years. A decrease in haplotypic and nucleotide variability was noted in the Central Caucasian populations of the little squirrel as compared to those from the Eastern Caucasus, which in general indicates the low viability of S. pygmaeus inhabiting the mountains of the Central Caucasus. [ABSTRACT FROM AUTHOR]

Parameters of hematopoietic tissue and peripheral blood in the Caucasian snow vole (Chionomys gud Satunin, 1909), a typical mountain species of small mammals, have been studied for the first time along a latitudinal–longitudinal (rather than altitudinal) gradient. It has been found that the blood of snow voles living at the same elevation (1800 m a.s.l.) in the maritime climate of the Western Caucasus and in the continental climate of the Central Caucasus has similar oxygen-carrying capacity, but this is provided by different mechanisms. The results of this study suggest that the natural conditions of the Western Caucasus are most optimal for the species. [ABSTRACT FROM AUTHOR]

Allozyme analysis of 18 Pinus sylvestris L. populations from seven landscape-geographic groups has been performed in the Greater Caucasus, Crimea, and Russian Plain. The results show that populations of the Mt. Elbrus region (isolated by high mountain ridges) are characterized by lower polymorphism and most distinct differentiation (at the level of geographic race) from other populations, which are differentiated from each other at the level of geographic groups. Genetic gradients (boundaries) between populations reach a maximum on transects across the Greater Caucasus Range, and Transcaucasian populations are more similar to populations of the Russian Plain, compared to North Caucasian populations, which confirms the hypothesis of ancestral connections between their gene pools. [ABSTRACT FROM AUTHOR]