The genetic structure of chum salmon (<Emphasis Type="Italic">Oncorhynchus keta</Emphasis> Walbaum) populations inferred from the nucleotide variation of the mitochondrial DNA cytochrome <Emphasis Type="Italic">b</Emphasis> gene

The nucleotide sequences of a fragment of the mitochondrial DNA cytochrome b gene were determined in 12 chum salmon populations from the Russian Far East. The level of genetic diversity in the chum salmon populations from the Iturup Island, northern coast of the Sea of Okhotsk, and Anadyr’ River was found to be higher than in the populations from Kamchatka and Sakhalin, which may be related to the history of their origin and dispersal. The proportions of intrapopulation genetic variability (F _CT) and interpopulation genetic variability within the groups (F _SC) account for 90.87 and 0.9%, respectively, and the intergroup component (F _ST) comprises 8.23%. The predominance of one haplotype, B1, which is common for all populations studied, and a low share of intergroup variability suggest the beginning of colonization by the species of the given region from a common source (group of founders) and a relatively recent time of divergence of the chum salmon populations from the region examined.