Washington [US], Jan 6 (ANI): A new study based on 297 ancient Scandinavian genomes analyzed along with genome data from 16,638 present-day Scandinavians unravels the complex relationships between geography, ancestry and gene flow in Scandinavia, spanning the Roman, Viking Age and later periods. A surprising increase in variation during the Viking Age suggests that gene flow to Scandinavia was particularly intense during this period.
An international study coordinated from Stockholm and Reykjavik examines the evolution of the Scandinavian gene pool over the past 2000 years. In this work, the researchers relied on historical and prehistoric through and from material excavated in Scandinavia. These ancient genomes were compared with genomic data from 16,638 contemporary Scandinavians. Because the geographic origins and dates were known for all these individuals, it was possible to resolve the evolution of the gene pool to a level never before realized.
Dr. Ricardo Rodriguez Varela of the Center for Paleogenetics, who analyzed all the data and extracted some of the ancient DNA used in the study, explains: “With this level of resolution, we not only confirm the Viking Age migration. We can also trace it to the eastern Baltic region, the the British-Irish islands and southern Europe. But not all parts of Scandinavia received the same amount of gene flow from these areas. For example, while British-Irish ancestry became widespread in Scandinavia, the East-Baltic ancestry mainly reached Gotland and central Sweden.” The gene pool bounced back after the Viking Age Another new discovery in this study was what happened to the gene pool after the Viking Age. The researchers were surprised to find that it bounced back in the direction of how it looked before the Viking Age migration.
Professor Anders Gotherström at the Center for Paleogenetics, who is a senior researcher on the study, is fascinated: “Interestingly, non-local ancestry peaks during the Viking Age while being lower before and after. The decline in current levels of extrinsic ancestry suggests that the Viking Age migrants had fewer children, or somehow contributed proportionately less to the gene pool than the people already in Scandinavia.” Yet a new discovery was the story of the northern Scandinavian gene pool. There is a genetic component in northern Scandinavia that is rare in central and western Europe, and the researchers were able to trace this component in northern Scandinavia through the last 1,000 years.
Dr. Ricardo Rodriguez Varela comments, “We suspected that there was a chronology for the northern Scandinavian gene pool, and it certainly proved that a later influx of Uralic ancestry into Scandinavia defines much of the northern gene pool. But if it is recent, it is comparatively so . For example, we know that this Uralic ancestry existed in northern Scandinavia already during the late Viking Age.” The study is based on a number of well-known Swedish archaeological sites. There are, for example, traces from the 17th-century warship Kronan, from Viking and Vendel Age boat burials in Mälardalen and from the migration-era ring fortress Sandby Borg on Öland.
Anders Gotherström concludes: “We worked on a number of smaller studies at different archaeological sites. And at some point it just made sense to combine them into a larger study on the evolution of the Scandinavian gene pool.
The study, which is published today in Cell, is an international venture with several partners, but it was led by Dr Ricardo Rodriguez Varela and Professor Anders Gotherstorm at Stockholm University, as well as Professor Agnar Helgason and Kristjan Moore at deCODE in Reykavijk. (ANI)