ИСТИНА

Kronotsky Lake (54o50’N; 160o15’E), the largest lake on the Kamchatka Peninsula, Russia, is located within the Kronotsky Biosphere Reserve. Isolated from ocean by waterfalls, lake fish fauna consists of only kokanee (residential form of Oncorhynchus nerka) and up to five sympatric forms of Kamchatka malma (Dolly Varden; Salvelinus malma) -long-nosed (Schmidti), longhead, white, dwarf and the river malma. Taxonomic status of Dolly Varden forms from the Kronotsky lake is still discussable. To reveal genetic differentiation and origin of sympatric Krontsky malma forms, we have sequenced D-loop and CytB genes (combined length 1573 bp) in 142 specimens from the lake and, as an outgroup, 54 specimen from the Kronotsky River below waterfalls (anadromous malma). The landlocked Dolly Varden forms and anadromous population have very different genetic structure. The majority of fish from the lake posses one of four most common haplotypes, while the other speciemen have unique haplotypes, distinct by one (rarely two) substitutions from the common haplotype. Anadromous malma from below waterfall presented by wide network of mtDNA haplotypes. Each of the four major lake haplotypes is also present within anadromous malma. Distribution of mtDNA haplotypes indicate that all forms of the Kronotsky lake Dolly Varden evolved from very small population of anadromous malma, landlocked in the lake system when volcanic dam cut the migration into the lake from the ocean. Since then, a number of unique haplotypes have been formed within the lake, which indicate that time of genetic isolation from the anadromous malma is concordant with dating of the lake origin - 12-14 kyr. Our data does not allow us to estimate genetic differentiation among different lake-dwelling forms, but strongly support the monophyletic origin of all forms within the lake. To estimate genetic differentiation and population structure, an extensive study of microsatellite variation will be conducted.