A large-scale study of the genetic history of Scandinavia over the last 2000 years has found increased patterns of migration during the Viking Age (750–1050 CE).
The study, published this week in the journal Cell, examined 48 new and 249 published ancient genomes recovered from archaeological sites and compared them to 16,638 modern individuals. The research team, led by members from led by Stockholm University and deCODE genetics in Iceland, were actually working on three separate studies for different archaeological sites, but then pooled together their resources for this much more expansive project.
Ricardo Rodríguez-Varela of Stockholm University, one of the lead authors, explains “when we were analyzing the genetic affinities of the individuals from different archaeological sites such as the Vendel period boat burials, Viking period chamber burials, and well-known archaeological sites like the Migration period Sandby borg ringfort, known for the massacre that occurred there [in] 500 CE, and individuals from the 17th-century royal Swedish warship Kronan, we start to see differences in the levels and origin of non-local ancestry across the different regions and periods of Scandinavia.”
The team organized their research into five periods: Pre-Viking (1–749 CE), Viking (750–949 CE), Late Viking (950–1099 CE), Medieval (1100–1349 CE), and Post-Medieval period (1350–1850 CE). They found that the Viking and Late Viking periods saw a great increase in migration from both the British Isles and the Baltic region into Scandinavia.
Those of British and Irish ancestry were predominantly coming to Denmark and southern Sweden. The researchers write:
This is perhaps not surprising, given the extent of Norse activities in the British-Irish Isles, starting in the 8th century with recurrent raids and culminating in the 11th century North Sea Empire, the personal union that united the kingdoms of Denmark, Norway, and England. The circumstances and fate of people of British-Irish ancestry who arrived in Scandinavia at this time are likely to have been variable, ranging from the forced migration of slaves to the voluntary immigration of more high-ranking individuals such as Christian missionaries and monks.
Meanwhile, those of Baltic origins can first be seen arriving on the island of Gotland and afterwards settling into central Sweden. “The increase of eastern Baltic ancestry in these regions during the Viking Age is consistent with historical sources attesting to contacts such as tributary relations, trade, conflicts, and treaties,” the article notes.
The researchers also found that of those arriving in Scandinavian during the Viking period, there were more women than men, more so from the Baltic region, and to a lesser extent from the British Isles.
This influx of new peoples into Scandinavia would decline in the later periods, making their impact on the region’s gene pool become less significant. Even in Scandinavia today, the levels of non-local ancestry in some regions are lower than those observed in the Viking to Medieval periods.
Overall, the findings show that the Viking period in Scandinavia was a very dynamic time, with people moving around and doing many different things. In future work, the researchers hope to add additional genetic data so they can learn more about how the ancestries that arrived during the Viking period were later diluted.
“We need more pre-Viking individuals from north Scandinavia to investigate when the Uralic ancestry enter in this region,” Rodríguez-Varela adds. “Also, individuals from 1000 BCE to 0 are very scarce, [and] retrieving DNA from Scandinavian individuals with these chronologies will be important to understand the transition from the Bronze Age to the Iron Age in this part of the world. Finally, more individuals from the Medieval period until the present will help us to understand when and why we observe a reduction in the levels of non-local ancestry in some current regions of Scandinavia.”
The article, “The genetic history of Scandinavia from the Roman Iron Age to the present,” by Ricardo Rodríguez-Varela, Kristjan H.S. Moore, S. Sunna Ebenesersdóttir et al., appears in Cell. Click here to read it.
Top Image: Courtesy of Cell / Creative Commons Attribution (CC BY 4.0)