Data from: Nuclear microsatellite and mitochondrial DNA analyses reveal the regional genetic structure and phylogeographical history of a sanguivorous land leech, Haemadipsa japonica, in Japan

Recent molecular studies have indicated that phylogeographical history of
Japanese biota is likely shaped by geohistory along with biological
events, such as distribution shifts, isolation, and divergence of
populations. However, the genetic structure and phylogeographical history
of terrestrial Annelida species, including leech species, are poorly
understood. Therefore, we aimed to understand the genetic structure and
phylogeographical history across the natural range of Haemadipsa japonica,
a sanguivorous land leech species endemic to Japan, by using nine
polymorphic nuclear microsatellites (nSSR) and cytochrome oxidase subunit
one (COI) sequences of mitochondrial DNA (mtDNA). Analyses using nSSR
revealed that H. japonica exhibited a stronger regional genetic
differentiation among populations (G'ST = 0.77) than other animal
species, probably because of the low mobility of land leech. Analyses
using mtDNA indicated that H. japonica exhibited two distinct lineages (A
and B), which were estimated to have diverged in the middle Pleistocene
and probably because of range fragmentation resulting from climatic change
and glacial and interglacial cycles. Lineage A was widely distributed
across Japan, and lineage B was found in southwestern Japan. Analyses
using nSSR revealed that lineage A was roughly divided into two population
groups (i.e., northeastern and southwestern Japan); these analyses also
revealed a gradual decrease in genetic diversity with increasing latitude
in lineage A and a strong genetic drift in populations of northeastern
Japan. Combined with the largely unresolved shallow polytomies from the
mtDNA phylogeny, these results implied that lineage A may have undergone a
rapid northward migration, probably during the Holocene. Then, the
regional genetic structure with local unique gene pools may have been
formed within each lineage because of the low mobility of this leech
species.