EN
To understand the relationship between social behaviour and gene distribution, we used microsatellite markers to resolve the spatial genetic structure of the sika deerCervus nippon Temminck, 1838 population on Kinkazan Island, a small island (9.6 km2) in northern Japan. We obtained 177 samples of deer which correspond to about 30% of the total population on the island. 126 were from a local population where each deer was individually identified, while 51 from other area on the island. Although there were no apparent geographical barriers on the island, the sika deer population showed local differentiation in its genetic composition. By comparing allele-sharing rates between gender and social categories, we demonstrated a higher genetic relatedness within males in a local group. The Assignment Index (AI) of each sex within a local group showed similar distributions. None of our analyses indicated a lower genetic relatedness among males than females, which contradicted our predictions based on the dispersal behaviour of males. Considering other factors, the results suggest that the range of male dispersal is quite limited on this island.