Molecular divergence and speciation of Baikal oilfish (Comephoridae): facts and hypotheses.

Sympatric speciation was studied in two sister species of cottoid fish from Lake Baikal (East Siberia): big golomyanka or Big Baikal oilfish (Comephorus baicalensis Pallas, 1776) and small golomyanka or Little Baikal oilfish (C. dybowski Korotneff, 1905). Analysis of nucleotide sequences of mitochondrial cytochrome b gene showed that the Little Baikal oilfish (LBO) formed a single population in the lake, whereas the Big Baikal oilfish (BBO) was divided into two genetic groups - BBOI and BBOII, which were not separated geographically.