Polymorphic microsatellites in the African freshwater snail, Bulinus forskalii (Gastropoda, Pulmonata)

Eleven microsatellites were isolated in the freshwater snail Bulinus forskalii, intermediate host for the medically important trematode Schistosoma intercalatum. Characterization in 60 snails from three populations of B. forskalii from Cameroon revealed 4 to 18 alleles per locus. Low observed heterozygosity but higher expected heterozygosity, high F-IS estimates, significant departures from Hardy-Weinberg equilibrium and genotypic linkage disequilibria all indicate that B. forskalii is a preferential selfer. High F-ST estimates suggest that effective dispersal is limited and genetic drift is an important determinant of genetic structure. The potential utility of the microsatellite primers in other closely related Bulinus species was explored.