Divergence of Salvelinus species from northeastern Asia based on mitochondrial DNA

Phylogenetic analysis of charrs of the genus Salvelinus was performed using PCR-RFLP analysis of mitochondrial DNA (mtDNA). Three fragments of mtDNA (ND1/ND2, ND5/ND6 and Cyt b/D-loop) were amplified by PCR and examined for restriction site variation using 13 restriction endonucleases. Analysis of 313 sites of over 7672 bp of charr mtDNA was conducted. Six phylogenetic lineages of the mtDNA were revealed, corresponding to six separate charr taxa: Salvelinus leucomaenis Pallas; Salvelinus levanidovi Chereshnev, Skopetz & Gudkov; Salvelinus taranetzi Kaganovsky; Salvelinus malma krascheninnikovi Taranetz; Salvelinus malma malma Walbaum and Salvelinus alpinus alpinus. The Levanidov (S. levanidovi) and white-spotted (S. leucomaenis) charrs represented the most divergent lineages. These are probably closest to a common ancestor of the genus. Salvelinus taranetzi was the next divergent lineage. Salvelinus malma krascheninnikovi was placed between S. leucomaenis and S. taranetzi. Salvelinus malma malma and S. a. alpinus were sister taxa, and were on the last branch to diverge. The divergence between S. m. malma and S. a. alpinus inferred from mtDNA nucleotide sequences was 1.1%; between S. m. malma and S. taranetzi 2.8%; between S. m. malma and S. m. krascheninnikovi 4%; between S. taranetzi, S. m. krascheninnikovi and S. a. alpinus 2.8%. Salvelinus levanidovi and S. leucomaenis were almost equally remote from the other charrs by some 9% and 7%, respectively. The extent of genetic differences between the northern S. m. malma populations and the European S. a. alpinus populations indicates that they diverged recently. The existence of many putative charr species with different divergence times in northeastern Asia suggests that this region may be one of the centres of speciation of the genus Salvelinus.