Nucleotide diversity of the fragment of cytocrhome oxidase gene subunit 1 of mitochondrial DNA in (Oncorhynchus Nerka) populations

Abstract

Purpose: to analyze the nucleotide diversity of the cytochrome oxidase gene fragment of the 1 mt DNA subunit in the Asian and American populations of sockeye salmon.Materials and methods. The material for analysis is nucleotide sequences obtained by the author for the sockeye salmon population of the Ola River, and for a number of Asian and American sockeye salmon populations, located in the Gene Bank (www.ncbi.nlm.nih.gov). 139 sequences were analyzed, the unifies number of nucleotide was 640. The statistical parameters are as follows: ps – the proportion of polymorphic sites, θ - the proportion of polymorphic sites taking into account the number of sites (i) ps /a1 = 1\ 1\i = 1\ 1 + ½ + 1/3 + … + 1/i, πT – nucleotide diversity, πs – average nucleotide diversity within a population, δST – interpopulation nucleotide diversity. NST – coefficient of nucleotide differentiation, NST = δST / πT. The dendrogram is built using the values of the so-called p-distances, using the UPGMA clustering method.Results. The nucleotide diversity of sockeye salmon from the Ola River (πT = 0,00505 (s=0,000080)) turned out to be slightly higher than in American populations (πT = 0,00403) (s=0,000002)). The coefficient of nucleotide differentiation NST and the number of polymorphic sites in Asian populations are higher than in American populations. Due to this, a higher level of nucleotide diversity was found in Asian sockeye salmon populations (πT = 0,00504 (s=0,000004)) than in North American ones. The nucleotide sequences of all individuals are divided into 2 groups. Individuals of these groups do not have territorial attachment, i.e. noted in both Asian and American populations. It is most likely that these groups formed as a result of Late Pleistocene climate fluctuations and the associated presence of two refugia on the Asian coast – the rivers of the northern coast of the Sea of Okhotsk and the rivers of the Kamchatka Peninsula, the second salmon, it is also assumed that two refugia will exist during the period of climate cooling, one in the area of the Alaska Peninsula, the second in the area of Vancouver Island. Almost all large populations of sockeye salmon are influenced by fishing and, in many cases, artificial farming. To reliably distinguish hatchery fish from sockeye salmon  produced in natural spawning grounds, the characteristic nucleotide sequence of the mtDNA cytochrome oxidase gene can be used.