[Genetic connections and differentiation of ground squirrels Marmotinae Pocock, 1923 (Rodentia, Sciuridae) from Palearctics].

Genetic distances between eight species of sousliks (Spermophilus) and five species of marmots (Marmota) were estimated on the basis of 39 biochemical loci. All taxa were shown to be genetically discrete. The genetic differentiation was minimal (Pfd = 11.3) between parapatric species of Palearctic sousliks of the suslicus pigmaeus group and Marmota species, intermediate (Pfd = 34.7) between allopatric sousliks species, and maximal (Pfd = 56.7) between representatives of different genera. The following trends were revealed in the geographic differentiation of the genus Spermophilus: (1) genetic similarity was associated with the geographic distance; (2) the eastern and western Palearctic phyla were markedly different genetically; (3) the eastern Palearctic forms exhibited higher differentiation than the western ones. The revealed speciation pattern is consistent with the general trend of temporal differentiation in Palearctic phyla and confirms the periodic speciation mode in the Palearctics.