Genetic Variability of Dolly Varden (Salvelinus malma), White-Spotted Char (S. leucomaenis), and Interspecific Hybrids from the Utkholok River (Northwestern Kamchatka)

The genetic variability of Dolly Varden, white-spotted char, and their interspecific hybrids for nine nuclear DNA microsatellite loci and the mtDNA CO1 gene was investigated. Significant genetic divergence between the two species of char for all microsatellite loci was shown (F-ST = 0.529; p < 0.001). Dolly Varden was characterized by significantly greater genetic variability compared to white-spotted char in terms of the average expected heterozygosity (H-E) and allelic richness (A(R)). Hybrids had intermediate H-E and A(R) values compared to their parents. Three haplotypes in the CO1 gene were revealed. All phenotypic white-spotted char individuals and the hybrids had one haplotype that was specific to S. leucomaenis. Specimens that were phenotypically identified as Dolly Varden had two haplotypes related to S. malma. Thus, the hybrids were produced by males of Dolly Varden and females of white-spotted char. The individuals with hybrid genotypes, except for one, were the first generation hybrids (F-1). One char may be a descendant of a hybrid crossbreeding with one of the parental species or a second-generation hybrid F-2, indicating that hybridization between the species studied is introgressive.