Analysis of Genetic Diversity in Coilia nasus Based on 2b-RAD Simplified Genome Sequencing

In the protection of migratory species, Coilia nasus has always been a research topic of very high interest in various countries because of the high economic value and the serious decline of resources. In this study, C. nasus were collected from the Shengsi Sea area, the Yangtze River estuary, the Taizhou section of the Yangtze River and Poyang Lake. By using 2b-RAD simplified genome sequencing technology, 63,110 SNP sites were screened, and the genetic diversity of each population was analyzed with SNP markers. The results showed that (1) the genetic purity of the four groups of populations was not high, with the need to further increase levels of genetic purity; (2) the genetic diversity in the four populations was high, indicating that they had strong adaptability to environmental changes and could easily expand their distribution and resource growth; (3) the F-ST values (0.112-0.142) of the four populations were higher, indicating that there was moderate genetic differentiation, but no independent population was formed. This study speculated that these migratory species may have the same spawning grounds and pointed out that the gene purity of C. nasus may have been polluted, and it is urgent to improve the purity in the protection of migratory C. nasus.