Viking expeditions to the West left their mark on the DNA

Scandinavian expansion, trade and raiding expeditions during the Viking Age meant an influx of genes from various directions westward, above all to the British Isles, and eastward to the Baltics, Russia, and the Byzantine Empire.

The flow from the west went to all of Scandinavia, but from the east to all of Gotland and Mälardalen and from the south to southern Scandinavia. But the traces in the genes of the North soon began to diminish, especially those from the East and South, researchers note in a new study, published in the journal Science. Go.

However, there is still a clear element of genes from the West. This means that men did not bring women home from the British Isles on Viking expeditions. For example, they may have lived there and returned home with their families during the centuries when the Danes dominated present-day Great Britain, and men from there may have settled in the Nordics.

Connections with the East, which left traces in the DNA of the Norsemen of the Viking Age, but have almost disappeared today, are of a different kind. Perhaps they were slaves brought here but did not form families with northerners. Many people – even from the West – don’t seem to have children like Northerners.

– They may belong to groups that are not allowed to start families or have children. But slaves were only what they could have been. They may have been diplomats and merchants or their wives. They may have been celibate priests and monks or come here for diplomatic marriages, says Anders Gotherström, a professor of evolutionary genetics at Stockholm University and one of the study’s lead authors.

Gene flow from the East appears to be female-dominated, but no bisexual dominance has been detected in gene flow from the West.

The researchers compared the DNA of 297 individuals from the beginning of our era to the 17th century and DNA from more than 16,000 modern northerners with that of other Europeans. The proportions of the various elements in today’s genetic mass have not been calculated, but Anders Gotherström estimates that only about half of the expected elements are present.

Curiously, the element of eastern genes is not present today in the parts of Sweden that were most affected by migration during the Viking Age – Gotland and Mälardalen – but in southern Sweden.

Of the DNA compared, 249 samples were analyzed previously, while DNA from 48 new ancient individuals was analyzed in the study. These included seven people from Sandby Castle in Åland, where a massacre took place at the end of the 5th century, and a dozen from the Cronon shipwreck that sank in the Baltic Sea in 1676.

The study, which began in 2018, also included new sequencing of 13 individuals from Sigtuna, after previous analyzes showed that the majority of the town’s population was of eastern origin.

DNA from 297 individuals was compared with DNA from 9,000 individuals in the Database of Modern European DNA. To see how much DNA flowed from the west, the researchers compared Irish with Lithuanians from the east and Sardinians from the south.

– We see three different gene pools. Medieval and historical materials are more similar to today’s Scandinavians than to those who lived before the Viking Age. Then we see gene flow to the Viking Age. Anders Gotherström says the gene pool was not the same before, during, and after the Viking Age.

In the study, the researchers also looked at DNA for northern Scandinavia. A new genetic element that came from the north and began to spread about 1,000 years ago can be seen there.

Icelandic researcher Agnar Helgason compared samples of ancient people in the north with Finns, modern Sami, North Americans and Central Asians. He discovered a common element called Uralic, a DNA element common among present-day Sami and Finns.

There are isolated cases such as a family buried in northern Norway from the Viking Age. During the 14th century, this element spread south, but it appears to have reached the whole of Scandinavia only in Kronen’s 1676 individual. The Uralic element is not only connected with Sami or Finnish identities.