Using mtDNA to evaluate pioneer colonization scenarios for early prehistoric southern Scandinavia

Abstract

DNA from living human populations can be used to infer their evolutionary and demographic histories, especially regarding initial dispersal events and subsequent population expansions. Southern Scandinavia was re-colonised by Late Palaeolithic hunter-gatherers beginning around 14 700 years BP, and the recent literature offers two competing hypotheses for the origins, direction and timing of this dispersal event. We present here the results of a study of maternally inherited mtDNA in 189 unrelated Danes, 64 of whom come from the island of Als and the remainder from various regions throughout the country. The mtRadius phylogeographic analysis tool is used to evaluate competing scenarios for the pioneer colonization of southern Scandinavia after the Last Ice Age. Our results are more consistent with an overall south-western dispersal trajectory for the maternally inherited mtDNA lineages. This contrasts with the current interpretation of the dispersal history of the paternally inherited Ychromosome. The discrepancy can be reconciled if more complex demographic scenarios are taken into consideration.