The modern man loves think a lot about themselves — take globalization, for example. Modern people would be forgiven for believing that with ease of travel and the historical migration of people around the world, most populations have a more diverse genetic record than in their supposedly more isolated past. But a new study that traces Viking DNA to modern Scandinavia suggests otherwise.
Certain interactions between different groups of people leave a lasting mark on the genes of their descendants, like how people of European descent tend to carry tiny bits of Neanderthal DNA in their genomes.
Other times, however, the genetic record of ancient interactions fades over time. According to a recent study, this appears to be what happened in the aftermath of the Viking Age in Scandinavia, which today includes Denmark, Norway and Sweden. Paleogeneticist Ricardo Rodrı́guez-Varelal and his colleagues at Stockholm University and the Center for Paleogenetics studied ancient DNA collected from people buried at sites across Scandinavia dating back 2,000 years. The researchers traced how the Scandinavian genome changed over time – and how immigrants from northern Europe influenced the gene pool.
The results were published Thursday in the journal Cell.
What’s new – Rodrı́guez-Varela and his colleagues compared some 300 genomes of people buried in Scandinavia over the past 2,000 years to the genomes of more than 16,000 modern Scandinavians as well as more than 9,000 people whose ancestors came from other places in Europe and Western Asia. They found that Viking Age Scandinavia was much more genetically diverse than modern Scandinavia.
Rodrı́guez-Varela and colleagues found ancestry threads from the eastern Baltic coast, far southern Europe, Great Britain and Ireland crossing the genomes of people from the Viking Age and early medieval Scandinavia.
That the Viking Age was diverse isn’t too surprising; a previous study found similar results, suggesting that ancient Norse people exchanged their DNA quite freely with other people they encountered — sometimes with the consent of all parties and sometimes not. The result was that Viking society was far from homogeneous and surprisingly cosmopolitan, especially in major cities.
The Viking Age was defined by maritime travel and trade. But DNA from people who lived during this era suggests that the Vikings weren’t the only ones sowing wild oats overseas. People also came from abroad to Scandinavia, and they did so in large enough numbers to show up in the region’s gene pool.
The twist – What is more surprising is that a few centuries after the end of the Viking Age, the genetic traces of these interactions had mostly faded. The people who came to Scandinavia during the heyday of Viking raids and trade – whether as traders, missionaries or enslaved captives – have all but disappeared from the gene pool of modern Scandinavia.
“The decline in current levels of external ancestry suggests that Viking period migrants either had fewer children, or somehow contributed proportionally less to the gene pool than people who were already in Scandinavia,” Anders Götherström said. , co-author of the article and a geneticist from the University of Stockholm. Reverse.
Here’s the background — Shortly after the fall of the Roman Empire, small kingdoms began to appear in Scandinavia. The newly rising ruling class needed money, and that need – along with a host of other factors, including climate change – fueled what became known as the Viking Age.
Even before the 793 CE raids on the monastery of Lindisfarne in Ireland marked the beginning of a new period of expansion, the Norse kingdoms had established trade networks reaching the Middle East and taken contracts from mercenaries in places as far away as Constantinople.
Archaeologists have found Arabic script woven into the fabric of clothing in Viking ship burials, making it clear that cultural exchange happened regularly – and human nature means that sometimes the exchange had to be personal too. But most of those individual stories of how people met, mingled, and interacted aren’t found in the genome many generations later; the signal is not strong enough, and eventually it fades into the background and is lost. On the contrary, the gene pool of a population reveals major large-scale trends over a long period of time, not individual relationships.
It is therefore perhaps unsurprising that the populations that most influenced the genetic heritage of the Vikings came from all over Europe, within trade networks, rather than from further afield.
Nor is it surprising that traces of ancestry from Baltic and southern European immigrants disappeared from circulation in Scandinavia a few centuries after the Viking Age. These migrants left a mark on Scandinavia’s gene pool enough to last a few centuries, but no more than that. British and Irish ancestry still appears in modern Scandinavian genomes, albeit in small amounts.
“This is perhaps unsurprising, given the extent of Norse activity in the British Isles from the 8th century…and culminating in the North Sea Empire in the 11th century,” Rodriguez writes. Varela and his colleagues in the article. Interactions with other people in other places were less intense and didn’t last as long.
Why is it important – If you get nothing else from this study, take this: genomes generally reveal only the most important and broadest traits of human interactions. Even the major events of the past are lost. The nuance is lost.
DNA tells part of the story, and archeology and written history tell other parts. The best way to understand the past is a combination of these pieces of evidence. For example, Rodrı́guez-Varela and colleagues found that the increase in Eastern Baltic ancestry in Gotland and central Sweden corresponded with the timing of treaties and other events. Without written history, we would not know what factors attracted people from the Baltic to Sweden. Without genetic history, we would not know the significant effects of these treaties and trade relations on people.
Testing your genetic ancestry with a homemade kit is fun, and many people are eager to brag about being Viking descendants for whatever reason. But studies like this suggest that this ancestral picture is more complicated than most people realize.
On the one hand, the ancient genomes challenge the idea that the Vikings were a force acting on the rest of the world without being influenced in return. People migrating to Scandinavia left their mark, suggesting that we shouldn’t think of the Vikings as doers and everyone in their path as passive. Scandinavia was also affected by these Viking Age interactions.
It is also clear that many people in modern Scandinavia are descended from people originating elsewhere, although these genetic clues have now been lost. This means that whatever your home DNA ancestry kit tells you (and there are plenty of reasons to take those results with a big grain of salt), your actual ancestry history is likely more complicated – and more diverse – than it looks on paper.