Data from: 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 recent periods (about 8000 and 1200 years ago). Populations in
different parts of Japan have their own sources. Natural migration in the
ancient period and artificial introduction in the recent period suggest
that the population distribution is affected by both the geohistory of
East Asia and the history of human expansion. In the background of the
historical migration and introduction, contemporary populations in the two
regions show different genetic patterns. Population divergence levels were
significantly correlated with geographical patterns in Japan, and
significantly correlated with human interventions variables in continental
East Asia, suggesting that long-term geographical isolation is likely the
major factor that shaped the genetic structure of contemporary populations
in Japan, while modern human uses are likely the major factor in
continental East Asia. Conclusions: Our preliminary results show a complex
population history and unusual genetic patterns in the contemporary
populations for a common freshwater snail and are of significance to
determine the historical formation and contemporary patterns of
biogeography in Japan and continental East Asia.