Variability of the Cytochrome b Gene of mtDNA of the Tundra Vole (Alexandromys oeconomus Pallas, 1776) in Northeast Asia and Alaska

The nucleotide sequence polymorphism and haplotype diversity of the cytochrome b gene in samples of the tundra vole ( Alexandromys oeconomus ) from Northeast Asia and Alaska were studied. Sixty-three haplotypes of the cytb gene (51 variants of Central Asian and 12 of Beringian genetic lineages), differing among themselves by 94 mutations, were found. The Upper Kolyma River is inhabited by voles of the Central Asian clade. A mixed population of this species in the basin of the Omolon River (right tributary of the Kolyma River) was found. In Chukotka and Alaska, only specimens of the Beringian phylogroup were found. The genetic differences between all samples are statistically significant. Genetic data of A. oeconomus populations of the Kolyma River basin, Alaska, and Northern Okhotomorye (Northern Sea of Okhotsk area) were compared. A total of 231 substitutions at 226 sites were found in the nucleotide sequence of the mtDNA cytochrome b gene in voles from both clades. The values of molecular diversity indices testify to the stability of populations with a high value of effective abundance over a long period of time. An analysis of the population gene pool formation was performed and a reconstruction of the complex dispersal history of this species across Northeast Asia was proposed.