PHYLOGENETIC RELATEDNESS OF 16 SPECIES OF THE BAIKAL LAKE COTTOIDEI BULLHEAD FISHES DEDUCED FROM PARTIAL NUCLEOTIDE-SEQUENCES OF MTDNA CYTOCHROME-B GENES

Partial nucleotide sequences of mitochondrial DNA (mtDNA) cytochrome b genes of 16 species of the Baikal Lake Cottoidei bullhead fishes from three families: Cottidae, Comephoridae, and Abyssocottidae, were dete rmined. Basing on the data obtained, phylogenetic trees were construct ed. We found that there exists a certain disparity between the phyloge netic conclusions drawn from the trees and some modern concepts on sys tematics and phylogeny of the group under study. For example, genetic distances between several species from the Cottidae family exceed by f ar those observed between the most remote species from different famil ies. Moreover, the branch leading to L. euristomus from the Limnocottu s genus significantly departs from the branches leading to other speci es of the genus. The phylogenetic trees obtained support the idea that the Baikal Cottoidea bullheads are a relatively young group (on the g eological time scale): they spread out ca. 2.0-2.5 mln years ago.