Search for genetic bases of species differences between Lake Baikal coregonid fishes: whitefish, C. baicalensis, and omul, C. migratorius
Bychenko, O.S.; Sukhanova, L.V.; Azhikina, T.L.; Sverdlov, E.D.
Baikal whitefish (Coregonus baicalensis Dybovski) and Baikal omul (Coregonus migratorius Georgi) are related genetically. They diverged from a common ancestor as recently as 10–20 thousand years ago. A large-scale search using subtractive hybridization techniques revealed minor differences between the genomes of Baikal whitefish and omul. Identified differential sequences corresponded to polymorphic, non-coding and genomic sequences that varied due to single nucleotide substitutions and short deletions. Many of these sequences include stretches identical to those of Тс1-like transposons widely spread in fish genomes. A comparative transcriptome analysis using SAGE (Serial Analysis of Gene Expression) method revealed different levels of a cDNA similar to a fragment of a Tc1-like transposon DTSsa4 in the brain of the two fish species under study. Just as other mobile elements, Tc1-like DNA transposons might be supposed to play an important role in the adaptive divergence of whitefish populations.