Evolution of the cytochrome b gene fragment from mitochondrial DNA in some Baikalian and non-Baikalian Cottoidei fishes

Partial nucleotide sequences of the cytochrome b [EC 1.6.2.2] gene located in mitochondrial DNA of 29 species of Cottoidei fishes (16 Baikalian and 13 non-Baikalian species) were determined. Pairwise analysis demonstrated that the gene evolution in Baikalian species may be characterized by a higher ratio of substitution mutations to synonymous substitutions. The causes of this difference are discussed. One of the possible explanations may be an enhanced rate of accumulation of substitution mutations accompanying intense speciation. Analysis of phylogenetic trees and of nucleotide sequences testifies to the recent origin of the Baikalian Cottoidei complex from one or a limited number of ancestral forms. Its evolutionary age does not exceed 2 million years.