Genetic diversity and population structure of native mitten crab (Eriocheir sensu stricto) by microsatellite markers and mitochondrial COI gene sequence.

Mitten crab (Eriocheir sensu stricto) is an indigenous and economically important species in East Asia. The genetic diversity and population structure of four wild native Eriocheir s. s. populations, from Yangtze (YZ), Oujiang (OJ), Minjiang (MJ), and Nanliujiang (NLJ) River basin, were studied. Genetic diversity of the four populations was evaluated by eight microsatellite and mitochondrial cytochrome oxidase subunits I (COI) markers. The polymorphism information content (PIC) values ranged from 0.7827 to 0.8580 and Shannon Wiener index (I) values varied from 2.0722 to 2.4088 respectively, according to microsatellite markers analysis. The haplotype diversity (h) values ranged from 0.52101 to 0.87097, while the values of nucleotide diversity (π) varied from 0.00139 to 0.02796 based on mitochondrial COI gene sequence. Four wild Eriocheir s. s. populations all showed high genetic diversity. As microsatellite analysis results, pair-wise FST values of YZ, OJ, MJ and NLJ populations were 0.1347, 0.1103 and 0.0943 respectively, which indicated that they were in medium genetic differentiation (0.05 < FST < 0.15). This was consistent with mitochondrial COI gene's conclusion. The bottleneck analysis was a hint that Eriocheir s. s. experienced bottleneck effect under SMM models of Sign Test and Wilcoxon Sign-rank Test. Based on genetic structure, YZ, OJ and MJ populations were in the same cluster separated from NLJ population. In summary, by microsatellite and mitochondrial COI markers analysis, all four Eriocheir s. s. populations had high genetic diversity, and genetic differentiation was consistent with geographical distance. Populations OJ and MJ were closer to population YZ genetically, and they had large genetic distance with NLJ population. This study provides a particularly important basis for mitten crab resources conservation and utilization in south China.