Population studies on the Aland Islands. I. Prediction of kinship from migration and isolation by distance.

Abstract

The population of the Aland Islands, situated in the Northern Baltic Sea between Sweden and Finland, has been relatively isolated until recent times. Currently the islands con tain about 21,000 Swedish-speaking inhabitants, primarily the descendants of a much smaller founder population (c. 5,200 in 1721). The archipelago is divided according to the Lutheran parishes. All the parishes or chapelries – with the exception of the only town parish, Mariehamn – have existed for more than 400 years. The main island with its surroundings consists of 1 town and 10 country parishes with about 18,000 inhabitants. The remaining 5 outer island parishes include about 40 inhabited islands. Parish records of births, deaths, and marriages, communion books, and poll-tax lists dating from the late 17th century provide a basis for historical and demographic studies. Subdivision into partially isolated populations derived from a small number of founders also makes the Aland Islands an excellent focus for population genetic studies. In the present report, the origin of 10,269 marriage partners in all the 15 Aland parishes in 1800–1849 have been used to obtain predictions of kinship within and among parishes using the migration analysis of Malécot. A marked association between geographical distances and predictions of kinship indicates that the distances between parishes were the major factor determining inter-parish mate exchange in the first half of the 19th century.