Microsatellite-based analysis of the genetic diversity and population structure of the seagrass species Thalassia hemprichii from southern Viet Nam

Abstract

Climate change, habitat loss, nutrient pollution, and other anthropogenic impacts cause seagrass degradation globally. Like other seagrass species, Thalassia hemprichii is threatened by these factors. A better knowledge about genetic diversity within and among populations would support and guide prudent conservation strategies. In Viet Nam, T. hemprichii is found mainly in two habitats including hard substratum in the open sea and the soft, muddy sand substratum in lagoons. In this present study, 106 individuals of T. hemprichii collected from eight pop- ulations along the southern coast of Viet Nam were used to evaluate the genetic diversity and population structure via 10 loci of microsatellite markers. Based on the pairwise FST, relatively low genetic differentiation was detected among T. hemprichii populations. Statistically significant pairwise population genetic differentiation was found among almost all populations. Cluster, structure, and AMOVA analysis also showed that the eight populations were separated into two groups in agreement with the two different habitat types. Significant positive correlations exist between geographic and genetic distances. The genetic diversity exhibitd by three of the eight populations suggests that these three populations need protection priority.