Novel polymorphic microsatellite markers for Bellamya and their application in population genetics of three species.

Bellamya is a widely distributed freshwater snail genus in China; however, its genetic diversity is completely unknown. Sixty-five novel microsatellite loci were isolated and characterized from a microsatellite-enriched library of Bellamya aeruginosa genomic DNA. Most of the 65 loci were successfully amplified. We found high polymorphic information content values for these loci, ranging from 0.235 to 0.892. There were 3 to 12 alleles per locus, and the HE and HO varied from 0.425 to 0.953 and 0.026 to 1.000, respectively. Fifteen loci deviated significantly from Hardy-Weinberg equilibrium after Bonferroni's correction. All 65 SSR markers were tested in an additional five Bellamya species, and 96.9% of the 325 locus/taxon combinations tested resulted in cross-species amplification. Seven polymorphic microsatellite markers were randomly selected for comparison among nine populations of three species. All populations had moderate to high genetic diversity. In genetic distance-based cluster analysis, the populations of B. aeruginosa and B. dispiralis formed species-based clusters, whereas populations of B. angularia did not. The three examined Bellamya species could be differentiated using SSR markers. These microsatellite loci should be useful for genetic diversity analysis, analysis of phylogenetic relationship, and species delimitation of Bellamya.