Genetic Variability of Pacific Rainbow Smelt Osmerus dentex (Osmeridae) from the Seas of Japan and Okhotsk according to the Data of Analysis of Microsatellite Loci and Mitochondrial DNA

The genetic diversity of Pacific rainbow smelt Osmerus dentex from the seas of Okhotsk and Japan has been studied based on nine microsatellite loci and the control region of mitochondrial DNA (940 base pairs). The lowest values of all parameters of genetic diversity of mitochondrial DNA were observed in the group of samples from the northern coast of the Sea of Okhotsk. The highest value of the haplotype diversity was found in the sample from the Sakhalin Island and in rainbow smelt from the Sea of Japan. The star-shaped topology of the genealogical structures indicates a rapid expansion of the abundance and the origin of all populations of the species from a single common ancestor from the main refugium. Based on the results of analysis of nuclear markers, we have revealed a statistically significant genetic structuring of rainbow smelt within its Pacific range (the coefficient of genetic differentiation (F-ST) is 0.033), which is adequately described by the model of isolation by distance. The greatest genetic differences in two types of markers from the other samples have been found in rainbow smelt from the Shkotovka and Botchi rivers of the basin of the Sea of Japan and from the Naiba River (Sakhalin). The observed patterns of genetic differentiation of Pacific rainbow smelt by the nuclear and mitochondrial markers complement each other well and are most likely associated with differences in the distribution of smelt larvae from the spawning grounds, which are determined by the differentiation of oceanographic conditions.