Abstract
Genetic population structure of the Neptune whelk (Neptunea arthritica) in northern Japan was estimated from six samples collected from Hokkaido and one sample from Aomori, in northernmost Honshu, using five polymorphic microsatellite DNA loci. Pairwise FST estimates indicated a genetic cline from eastern and northeastern Hokkaido to southern Hokkaido and northernmost Honshu. The individual-based assignment method and analyses of molecular variance suggested three geographic groups within this cline. The observed population structure was most likely influenced by isolation-by-distance with restricted gene flow, as suggested by the significant correlation between genetic and geographic distance for the entire region examined. The inferred restriction of gene flow is likely due to the poor dispersal ability of this species, which has a benthic, sedentary life history and passive dispersal along the coasts. The observed genetic structure of N. arthritica will be useful for conservation and fisheries management of this species.
