Charrs of the genus Salvelinus (Salmonidae): hybridization, phylogeny and evolution

Evolutionary history, systematics and taxonomy of charrs of the genus Salvelinus and especially of the representatives of the S. alpinus-S. malma species complex remain confused that is connected with a substantial ecological and morphological flexibility of this group and with supposed ancient hybridization between some taxa. For the analysis of phylogenetic relationships and introgressive hybridization between the species of the genus Salvelinus including three endemic species from Lake El'gygytgyn and all main representatives of the S. alpinus-S. malma species complex, nucleotide sequences of the mtDNA control region and two nuclear genes (ITS1 and RAG1) were analyzed. The differences in the topologies of individual gene trees, among other reasons, were connected with incomplete lineage sorting and historical introgressive hybridization between certain taxa. Several cases of mtDNA capture by different taxa and phylogenetic groups were proposed. Main phylogenetic groups of the S. alpinus-S. malma species complex were revised. The origin and phylogenetic relationships of southern Dolly Varden from North America were not unambiguously defined. We proposed that introgressive hybridization had an important role in the evolutionary history of charrs, in particular, in the appearance of a high level of morphological, ecological and taxonomical diversity.

Automated summary

The evolutionary history, systematics, and taxonomy of charrs of the genus Salvelinus, particularly the S. alpinus-S. malma species complex, remain confused due to ecological and morphological flexibility of the group and historical hybridization. Analysis of phylogenetic relationships and introgressive hybridization between species revealed complexities due to incomplete lineage sorting and hybridization, suggesting the important role of introgressive hybridization in the evolutionary history of charrs and the appearance of high diversity in morphology, ecology, and taxonomy.