Genetic variation in Brac, Croatia.

A serological survey of the Dalmatian island of Brac (Croatia), based on a total sample of 747 subjects, shows considerable local genetic variation. While the overall gene frequencies are much as expected from the island's geographical position, the local genetic heterogeneity is made up of differences between the inland and coastal villages, differences between the two coastal areas, and variation among the older inland villages. This heterogeneity is interpreted as deriving from the settlement process (founder effect), random differentiation, and the essentially local marriage pattern.