Molecular Phylogeography of Lake Baikal Coregonid Fishes
Sukhanova, L.V.; Smirnov, V.V.; Smirnova-Zalumi, N.S.; Belomestnykh, T.V.; Kirilchik, S.V.
There is no common consensus on the genealogical/phylogeographical history of coregonid fishes in Lake Baikal. In this study, we included nearly all the true whitefishes inhabiting the basins adjacent to Lake Baikal into a molecular-phylogenetic analysis allowing us to draw conclusions regarding the phylogeography of Lake Baikal coregonid fishes. Nucleotide sequences of the cytochrome b gene in the mtDNA were examined. We establish that all Baikal coregonid fishes belong to a monophyletic group of true whitefishes with some divergent clades. The formation of divergent clades (radiation of true whitefishes) appears to be a star phylogeny. Baikal pidschian (lacustrine/ riverine) Coregonis lavaretus pidschian (Gmelin) is in a clade together with some inhabitants of the Yenisei basin and very close to Yenisei riverine hump-nosed whitefish C. l. pidschian natio fluviatilis Issatchenko. Baikal omul (anadromous) C. autumnalis migratorius Georgi and Baikal whitefish (lacustrine) C. l. baicalensis Dybowski are the only members of a second clade. The results suggest: 1) recent penetration of a Baikal pidschian ancestor into Lake Baikal (probably with the appearance of the Angara River flow from the lake, about 60, 000 years ago), i. e., allopatric origin; and 2) recent sympatric origin of Baikal omul (pelagic) and Baikal whitefish (benthic), probably after the last glaciation (about 10, 000 years ago). A hypothesis of repeated sympatric isolation of pelagic and benthic forms within the lake is suggested.