ИСТИНА

Study of patterns of contemporary genetic diversity and their link to the demographic and microevolutionary processes in populations is the key point in insight into extremely complex intraspecifi structure common to pacific salmon. The diversity and distribution of mtDNA control region haplotypes in sockeye salmon from 19 river systems across the species Asian range (from Chukchi Peninsula to the South Kuril Islands) was investigated. Two mass haplotypes (Hap_1_10T and Hap_2_13T) were revealed. All the sequence variants were distributed among two haplogroups in compliance with the dominant haplotypes. Along the Asian coast of the Pacifi Ocean there was no clearly pronounced clinal character in the change in haplotypes frequencies. Howevere, the presence of both haplogroups in most populations in approximately equal proportions indicates that the entire Asian part of the sockeye range is a zone of secondary contact. The diversity of the fist haplogroup was higher, but its main fraction fell on the samples from the middle reach of Kamchatka River, which could be a refugium during the last glaciation. We have every reason to believe that Hap_2_13T had more ancient origin and the Hap_1_10T was formed somewhat later, apparently in Asia. We hypothesize that the beginning of the Holocene transgression marked the extremely rapid (explosive) distribution of this species throughout the entire modern range, and watersheds were colonized simultaneously by individuals from diffrent geographical areas, both northern (Alaska or the Beringia region) and southern (Japan and the South Kuril Islands), as well as from the Central Kamchatka refugium.