A DNA study of Vikings shows they were more genetically diverse than modern Scandinavians

A DNA study of Vikings shows they were more genetically diverse than modern Scandinavians

Modern man likes thinking a lot about yourself – let’s take globalization for example. Modern humans would believe that due to the ease of travel and the historical migration of peoples around the world, most populations have a more diverse genetic record than they had in their supposedly more isolated past. But a new study tracing Viking DNA to modern Scandinavia suggests otherwise.

Some interactions between different groups of people leave a long-lasting mark on their descendants’ genes, such as the way people of European descent tend to carry tiny bits of Neanderthal DNA in their genome.

In other cases, however, the genetic record of old interactions fades over time. According to a recent study, this appears to have happened after the Viking Age in Scandinavia, which today includes Denmark, Norway and Sweden. Paleogeneticist Ricardo Rodrı́guez-Varelal and his colleagues from Stockholm University and the Center for Paleogenetics studied ancient DNA collected from people buried 2,000 years ago at sites across Scandinavia. Researchers tracked how the Scandinavian genome changed over time – and how immigrants to northern Europe affected the gene pool.

The results were published in the journal on Thursday cell.

What’s new – Rodrı́guez-Varela and his colleagues compared about 300 genomes from people buried in Scandinavia over the past 2,000 years with the genomes of more than 16,000 modern Scandinavians and more than 9,000 people whose ancestors came from elsewhere in Europe and western Asia . They found that Viking-age Scandinavia was genetically much more diverse than modern Scandinavia.

This person, who died in the wreck of the Swedish warship Kronan in 1676, unknowingly made a posthumous contribution to the study. Lars Einarson

Rodrı́guez-Varela and his colleagues found ancestral threads originating from the eastern Baltic Sea coast, the extreme southern edge of Europe and Great Britain and Ireland running through the genomes of people from the Viking Age and early medieval Scandinavia.

That the Viking Age was diverse is not too surprising; A previous study found similar results, suggesting that ancient Scandinavian peoples shared DNA fairly freely with the 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 large cities.

The Viking Age was characterized by sea voyages and trade. But the DNA of people living in this age indicates that the Vikings were not the only ones who sowed wild oats overseas. People also came to Scandinavia from abroad, in sufficient numbers to appear in the region’s gene pool.

The turn – More surprisingly, 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 raiding and trading – whether they were merchants, missionaries or enslaved prisoners – have all but disappeared from the gene pool of modern-day Scandinavia.

“The decrease in the current number of external ancestors suggests that the Viking Age migrants had fewer children or somehow contributed proportionally less to the gene pool than the people who were already in Scandinavia,” says Anders Götherström, study co-author and geneticist from the University of Stockholm The opposite.

Here is the background – Shortly after the fall of the Roman Empire, small kingdoms arose in Scandinavia. The newly ascended ruling class needed money, and that need – along with a host of other factors, including climate change – fueled what came to be known as the Viking Age.

Ancient DNA samples have had an eventful journey from muddy archaeological sites to pristine genetics labs.David Diaz del Molino

Even before the raids on the monastery of Lindisfarne in Ireland in 793 AD marked the beginning of a new phase of expansion, the Scandinavian kingdoms had established trade networks that stretched as far as the Middle East and contracted out mercenaries in places as far away as Constantinople.

Archaeologists have found Arabic writing woven into the fabric of clothing in Viking boat burials, making it clear that cultural exchanges were regular – and human nature means that sometimes the exchanges must have been personal too. But most of these individual histories of how people met, mingled, and interacted didn’t make it into the genome several generations later; the signal is not strong enough and eventually fades into the background and is lost. Rather, a population’s gene pool reveals large, large-scale trends over a long period of time, not individual relationships.

It is perhaps no surprise, then, that the populations that most influenced the Viking gene pool came from across Europe, within reach of trade networks, and not further afield.

Nor is it surprising that traces of ancestry from Baltic and southern European immigrants were phased out in Scandinavia within a few centuries of the Viking Age. These migrants left enough traces in the Scandinavian gene pool to last a few centuries, but no longer. However, British and Irish ancestry still shows up in modern Scandinavian genomes, albeit in small amounts.

“This is perhaps not surprising given the scale of Norse activity in the British Isles, which began in the eighth century … and culminated in the North Sea Empire in the eleventh century,” Rodriguez-Varela and his colleagues write in the paper. Interactions with other people in other places were less intense and didn’t last quite as long.

Why it matters – If you take away nothing else from this study, take this: genomes typically reveal only the largest and broadest swaths of human interactions. Important events in the past are also lost. nuances are lost.

DNA tells part of the story, and archeology and written history tell other parts. The best way to understand the past is through a combination of these lines of evidence. For example, Rodrı́guez-Varela and his colleagues found that the increase in East Baltic ancestry in Gotland and central Sweden coincided with the timing of treaties and other events. Without written history, we wouldn’t know what factors drew people from the Baltics to Sweden. Without genetic history, we would not know the important outcomes of these contracts and trades between humans.

Testing your genetic ancestry with a home kit is fun, and many people are eager to brag about Viking ancestry for some reason. But studies like this suggest that this ancestral picture is more complicated than most people realize.

For one thing, ancient genomes challenge the notion that the Vikings were a force that affected the rest of the world without being affected in return. People migrating to Scandinavia left their mark, suggesting that we shouldn’t think of the Vikings as actors 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 who originally came from elsewhere, although these genetic clues have now been lost. That means the actual history of your ancestors is likely more complicated — and more diverse — than it appears on paper, whatever your DNA ancestry kit at home tells you (and there are plenty of reasons to take those results with a hefty grain to take salt). .

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