Genetic Diversity and Structure of Chinese Chum Salmon (Oncorhynchus keta) Between Wild and Hatchery Populations Based on SSR Markers

Abstract

The study was aimed at analyzing the genetic diversity and genetic structure of released populations and wild populations of chum salmon (Oncorhynchus keta) in the Tumen River Basin, and evaluating the effects of stock enhancement on the genetic diversity of wild populations. From 2014 to 2019, a total of 682 DNA samples from six wild populations and two hatchery populations were genotyped by using 10 pairs of self-developed microsatellite markers of chum salmon. Genetic diversity parameters and population structure were calculated by Cervus3.0, Structure2.3.4, Arlequin 3.5.2.2, GraphPad Prism and GenALEx 6.502. The results showed that the polymorphic information content (PIC) of 10 microsatellite loci ranged from 0.787–0.932, showing highly polymorphism. The average number of different alleles (NA) was 11.138 ± 0.999, the observed heterozygosity (Ho) and expected heterozygosity (HE) were 0.680 ± 0.058 and 0.784 ± 0.034, respectively. Shannon diversity index (I) was 1.872 ± 0.119. The inbreeding coefficient number (FIS) was 0.129 ± 0.054, indicating a certain degree of inbreeding. The population of chum salmon was divided into three groups by Bayesian genetic structure analysis and principal coordinate analysis, and there was significant genetic differentiation among the groups. AMOVA analysis revealed that most of the genetic variation came from within the population 87.77%, and 12.23% of the genetic variation came from between the populations. At present, the stock enhancement of chum salmon has no obvious effect on the genetic structure of wild population. Consequently, this study provides a scientific stock enhancement strategy as well as living resources database construction of O.keta.