Population structure of the spotted babylon, Babylonia areolata in three wild populations along the Chinese coastline revealed using AFLP fingerprinting

Many marine gastropods are sedentary as adults but have planktonic larvae which can potentially be dispersed over large distances. Consequently larval transport is expected to play a prominent role in facilitating gene flow and determining population structure. The spotted babylon (Babylonia areolata) is a dioecious species possessing an approximately two week planktonic larval stage. We analyzed the population structure of the spotted babylon using amplified fragment length polymorphism (AFLP). One hundred and sixteen AFLP loci were analyzed in 63 individuals from three populations and revealed a high level of genetic diversity, with all individuals harboring a unique banding pattern. AMOVA results and an assignment test revealed that population differentiation was present. PCoA, pairwise FST and UPGMA tree all revealed that gene flow might be present only on a small geographic scale (around 160 km), but, over a large distance (around 1000 km), only reduced gene flow occurred. A mantel test indicated a highly significant positive correlation between genetic differentiation and geographical distance.