Genetic Variation and Phylogenetic Relationships of Northern Pike (Esox lucius L.) Populations from Some Rivers of Russia

Data on the structure and variability of the nucleotide sequence of the mtDNA cytochrome b gene of the northern pike Esox lucius L. from the rivers of the Kolyma, Volga, Don basins and the Anadyr River were obtained. Unique haplotypes were found, indicating limited gene flow between the studied populations. Northern pikes from the Volga and the Anadyr have a high level of genetic diversity. Low genetic diversity was noted in some populations of the Kolyma and Don basins. Phylogenetic analysis of the nucleotide sequences of the cytochrome b gene showed the presence of three genetic strains, A, B, and C, having a common root of origin. The high level of differentiation of the identified strains is apparently caused by the long-term reproductive isolation of the northern pike in several refugia, which were the source for the circumpolar distribution of this species.