Analysis Of Genetic Diversity In Seven Populations Of Misgurnus Anguillicaudatus From Four Water Systems Using Microsatellite Markers

The loach Misgurnus anguillicaudatus is a kind of small fish that widely distributed in Eurasia especially in China. It can be found in almost all rivers, lakes, streams, rice fields, ponds and so on. Loach has many merits such as high value of nutrition, high good quality and medicinal value, therefore the consumption of Misgurnus anguillicaudatus is very prevalent in China, Korea and other Asian countries. However, the production of wild Misgurnus anguillicaudatus is declining with environmental degradation every year. This study aimed to provide the basis for species resource and protection through analysis of genetic diversity and structure of loach in our country.In this study, seven Misgurnus anguillicaudatus populations that respectively come from the Heilongjiang River, the Yellow River, the Yangtse River and the Pearl River were analyzed by using six microsatellites markers, we analyzed genetic diversity from six microsatellites which were obtained and used to determine the genetic diversity of 7 loach populations. Meanwhile,69 alleles were totally identified and their sequence were obtained via PCR. The number of alleles (Na) and effective alleles (Ne) ranged from 7 to 16 and 3.046 to 5.515. Observed heterozygosity (Ho) values varied between 0.2023 and 0.4081 and the expected heterozygosity (He) values varied between 0.6730 and 0.8202, which indicated that the seven populations owned a rich genetic diversity. All seven microsatellite loci were polymorphic, with polymorphism information content (PIC) values ranging from 0.643 to 0.796. HeiLongjiang population, AnHui population and GuangDong population were detected for deviating from Hardy-Weinberg equilibrium at all microsatellite loci and another 4 populations deviated from Hardy-Weinberg equilibrium at part microsatellite loci. The coefficient of gene differentiation between populations (Fst) was 0.333, which illustrated about 33.3% of total genetic variation was resulted from differences among populations. The values of Fis ranged from 0.1666 to 0.4214 and all of them were larger than zero, which indicated serious inbreeding intra-population. It may be resulted from Misgurnus anguillicaudatus’s life habit of inhabiting in suffer layer of mud of shallow water and small range of activity. A Neighbor-Joining Tree of 7 populations of Misgurnus anguillicaudatus on Nei’s genetic distiance were conducted and the cluster analysis showed that HeiLongJiang, JiangSu, AnHui and GuangDong populations were allocated into one cluster, and GuangXi, GanSu and ChongQing populations were allocated into another cluster. The assignment test between HeiLongJiang population and JiangSu population showed that some individuals of HeiLongJiang population were assigned into JiangSu population. This study demonstrated that wild loach population has been disturbed by human people and some sustainable management should be implemented to protect local genetic resource.