Genetic structure of the Azores: marriage and inbreeding in Flores.

Flores is one of the smallest and most westerly islands of the Atlantic archipelago of the Azores. This preliminary account of the population's demography and genetic structure uses dispensations to contract consanguineous marriages taken from the Roman Catholic marriage registers in order to estimate mean inbreeding rates in the population over the period 1860-1980. Comparisons are made with inbreeding rates on the Portuguese mainland and elsewhere in Western Europe, and reasons suggested to explain the rather high rates of inbreeding encountered on Flores.