1. ¹Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
2. ²deCODE Genetics, Sturlugata 8, 101 Reykjavik, Iceland
3. ³Institute of Biological Anthropology, University of Oxford, Oxford OX2 6QS, UK

Correspondence: S Goodacre, Current address: Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK. E-mail: s.goodacre@uea.ac.uk

⁴These authors contributed equally to this work

Deceased

Received 17 August 2004; Accepted 31 January 2005; Published online 6 April 2005.

Abstract

The Viking age witnessed the expansion of Scandinavian invaders across much of northwestern Europe. While Scandinavian settlements had an enduring cultural impact on North Atlantic populations, the nature and extent of their genetic legacy in places such as Shetland and Orkney is not clear. In order to explore this question further, we have made an extensive survey of both Y-chromosomal and mitochondrial DNA (mtDNA) variation in the North Atlantic region. Our findings indicate an overall Scandinavian ancestry of 44% for Shetland and 30% for Orkney, with approximately equal contributions from Scandinavian male and female subjects in both cases. This contrasts with the situation for the Western Isles, where the overall Scandinavian ancestry is less (15%) and where there is a disproportionately high contribution from Scandinavian males. In line with previous studies, we find that Iceland exhibits both the greatest overall amount of Scandinavian ancestry (55%) and the greatest discrepancy between Scandinavian male and female components. Our results suggest that while areas close to Scandinavia, such as Orkney and Shetland, may have been settled primarily by Scandinavian family groups, lone Scandinavian males, who later established families with female subjects from the British Isles, may have been prominent in areas more distant from their homeland.