We presented some data on the demographic and mating structure of Tobishima Island, in Yamagata Prefecture, evaluated some genetic parameters as a basis for the analysis of regional variation in physical traits, and compared the results with those from other island communities in Japan.
Tobishima was found to have a hierarchic population structure in which strong genetic isolation existed not only among the villages on the island but also between the island and the neighboring populations. The villages on the island were found to have effective population sizes between 68 and 120, effectivemi gration rates between 0.0619 and 0. 1902, and average inbreeding coefficients between 0.0387 and 0.0500. The corresponding breeding isolation coefficients were between 4.2 and 15. 2, suggesting that stochastic factors have brought about regional genetic variations among the villages and between Tobishima and the neighboring communities.
The Journal of the Anthropological Society of Tokyo