Human−geographic effects on variations in the population genetics of Sinotaia quadrata (Gastropoda: Viviparidae) that historically migrated from continental East Asia to Japan

Background: Anthropogenic factors potentially affect observed biogeographical patterns in genetic variations of populations, but the effects of ancient human activities on the original patterns that were created by natural processes are unknown. Sinotaia quadrata, a widely distributed freshwater snail species in East Asia, was used to investigate this issue. It is unclear if S. quadrata in Japan was introduced from China, and how different human uses and varying geographic patterns affect the genetic structure of contemporary populations between the two regions. Thus, we investigated the population history of S. quadrata and detected its genetic structure in Japan and continental East Asia.

Results: S. quadrata populations first naturally migrated from continental East Asia to Japan, which is associated with the ancient period in Japanese geohistory (about 70,000 years ago). They were then artificially introduced in association with agriculture expansion by human movements in two rec...