Microsatellite-based study of population genetics of Crassostrea hongkongensis in Southern China

Abstract

The Hong Kong oyster (Crassostrea hongkongensis) is endemic and one of the most important economic and extensively cultured oyster species along the southern coastal areas of China. However, limited information is available about its genetic variation and genetic structure. In this study, we analyzed genetic variation at twelve microsatellite DNA loci in eleven locations throughout the distribution of C. hongkongensis in the Sourthern China. Similarly to other cupped oyster species, a high level of genetic diversity was observed in all sampled populations. Populations exhibited significant genetic differentiation, and could be divided into four genetically distinct and geographically related groups: Guangxi group, the eastern Guangdong group, the western Guangdong group and Fujian group. The highest local differentiation was observed between the samples from Guangxi versus Guangdong and Fujian, which are separated by the Leizhou Peninsula. In addition, significant genetic differentiation was observed between the samples from the western Guangdong versus the eastern Guangdong, which are separated by the Pearl River estuary. Geographic isolation is one of the most important factors causing genetic differentiation among populations of C. hongkongensis. Additionally, the differentiation between some populations may be caused by salinity of seawater and runoff from the Pearl River. The significant genetic differentiation among populations implies that translocation of individuals for aquaculture should be properly managed for the preservation of genetic diversity and eventual local adaptation in natural populations.