Abstract：The Chinese mitten crab is an indigenous species in China, its hatchery production and larval farming have been performed almost exclusively in aquaculture farms for many years. It is worthy to know whether the genetic diversity of cultured crab has been changed in the closed off or half-closed off farm. The genetic diversity of Chinese mitten crab (Eriocheir sisensis) was investigated in three cultured populations (Jiangsu, Anhui and Liaoning Province, China) and wild population in Yangtze River by using 10 microsatellite markers. The results showed that the mean effective number of allele (Ne) of four populations were 8.77, 6.94, 8.71 and 9.03 respectively, the mean observed heterozygosity (Ho) was from 0.70 to 0.75, the mean expected heterozygosity (He) was from 0.87 to 0.90, the mean polymorphism information content (PIC) was from 0.84 to 0.87, the level of genetic diversity of the wild population was higher than that of the cultured population. Coefficient of genetic ddifferentiation F-statistic(FST) among populations ranged from 0.0123 to 0.0207. Analysis of molecular variance (AMOVA) revealed that a higher portion of variations existed within individuals, while lower portion existed among populations. FST and AMOVA analysis across all populations indicated the low level of divergence among the populations. The NJ clustering tree based on DA genetic distance demonstrated that there were two different groups: one being composed of cultured population in Jiangsu and wild population in Yangtze River, and the other of cultured populations in Anhui and Liaoning. A hundred and seven individuals obtained from different place could be grouped into two potential populations based on the genetic structure, the crabs cultured in Jiangsu and the wild crabs in Yangtze River were grouped into one population; the crabs cultured in Anhui and Liaoning were grouped into another population. These data demonstrated that the cultured mitten crab is in high levels genetic diversity and exhibite low levels of genetic variation as compared with wild population. There is potentiality for breeding selection.
