The perplexing population genetic structure of Bellamya purificata (Gastropoda: Viviparidae): low genetic differentiation despite low dispersal ability

Abstract

Bellamya purificata is a widely distributed Chinese freshwater snail. It plays a significant role in ecosystem services. However, its natural habitats are under severe threat due to fragmentation and loss. In order to estimate the genetic diversity and population structure of B. purificata, 182 individuals from eight locations throughout its distribution across China were sampled. Seven microsatellite loci and the mitochondrial COI gene were genotyped. Our results showed that (1) the genetic diversity of B. purificata was high in all studied populations; (2) a low level of genetic differentiation existed among the eight populations with little restriction to gene flow; (3) no clear geographic structure was revealed by either Bayesian clustering, haplotype networks or AMOVA; (4) effective population size (Ne) was moderate to high for all studied populations. The results of Bayesian Skyline plot analysis detected unstable population sizes through time for most populations. Passive dispersal during flooding events, zoochoric dispersal, possibly anthropogenic translocations and the large population sizes might be the major reasons for the lack of differentiation among Chinese B. purificata populations.