DNA analysis of 442 Viking skeletons rewrites the story of Viking culture

Say the word ‘Viking’ and note how your brain makes associations and begins to create a story. The narrative is not likely to be quiet and peaceful. In all probability, it will be fast and fierce with equal parts honour, power, conquests, lechery and an all-consuming, compelling wanderlust, garnished with frequent murder, burnings, abductions and drunken antics. The clash of crossing swords and metallic smell of blood meld to produce a drama both violent and life-affirming.

This is the way Vikings are often portrayed in books and films. Even though these images are not entirely wrong, the Viking culture – which was geographically centred in Scandinavia between 800 and 1050 AD – had many hitherto undocumented facets and nuances.

However, documentation was recently presented in a research article in one of the world’s most prestigious scientific journals, Nature. And as a front page story, no less. It doesn’t get much better than that!

The article was written by an international research team of 80 scientists specialising in archaeology, epidemiology, forensic medicine, evolutionary genetics, bio-statistics, protein research, biological psychiatry, history and analysis of ancient DNA.

The project was headed by Professor Eske Willerslev, Professor Thomas Werge, Professor Rasmus Nielsen and Assistant Professor Ashot Margaryan, all from the Lundbeck Foundation GeoGenetics Centre at the University of Copenhagen.

Viking skeletons
But what new knowledge can this large research team give us about the Vikings and Viking culture – or the Scandinavian culture, as archaeologists prefer to call it? And how did they go about gathering this knowledge?

The keyword is skeletons – 442 skeletons in all from the Viking Age, which were subjected to DNA analysis at the Lundbeck Foundation GeoGenetics Centre. The centre uses a particularly powerful DNA sequencing technique – Illumina – to perform very complex analyses of ancient DNA. The skeletons originate from Viking graves in Scandinavia, Greenland, Ukraine, Poland, Russia and the UK, and all 442 were sequenced.

In addition to the complete DNA profile of each of the 442 Vikings, the scientists were able to study a wide range of other factors; for instance, the incidence of genetic risk variants that analyses of present-day DNA link to a variety of diseases.

With funding from the Lundbeck Foundation, and with the help of DNA analyses of 5,000-year-old human skeletons (the oldest of which is more than 30,000 years old), Eske Willerslev and Thomas Werge have been working since 2018 on a large-scale project that seeks to identify the origin of brain disorders. These include neurological diseases such Alzheimer’s and Parkinson’s and psychiatric disorders such as schizophrenia and ADHD.
The analyses of the DNA of the 442 Vikings are an element of this project, and the skeletons were tested for more than 100,000 risk variants, which in present-day DNA are associated with schizophrenia.
These variants were most commonly found in the Norwegian skeletons and, statistically, the incidence exceeded the findings in samples of present-day Scandinavians.

However, Professor Thomas Werge explains that the researchers are cautious about drawing conclusions from this find, and he adds that, in general, ‘making deductions about diseases based on ancient DNA samples is not straightforward. There’s no standard as regards interpretation, and this is the first time we’re attempting to identify psychiatric risk variants in ancient samples.’

Therefore, in order to use contemporary knowledge about diseases to help us understand the disease risk in Viking DNA, we need to know whether today’s Scandinavians and the Vikings ‘are genetically fairly similar. And we are,’ says Professor Werge.

The researchers studied a total of 16 different traits in the DNA from the Viking skeletons found in Scandinavia, and in addition to the risk variants for schizophrenia, they looked at hair colour and predisposition for height, says Professor Eske Willerslev:

‘And now the fun starts, so to speak, because this is where the stereotypical perception of the “blonde, Scandinavian Viking” dies a sudden death! It’s certainly true that there were lots of blonde Vikings, but there were also dark-haired Vikings and Vikings with mousey-coloured hair. The whole idea that the Vikings were a kind of “Arian race” is pure rubbish. And the explanation is simple: the genetics that characterised people of the Viking culture had roots in both Asia and southern Europe. We could see this when we analysed the over 400 skeletons. We could also see that these people immigrated just as the Viking culture was really gathering momentum – which may even have been due to the migrations.’

With regard to height, the analyses showed that the Vikings were highly predisposed to being tall. However, the researchers are not able to say whether this applied to the entire population.

Four brothers fell in the same battle
The analyses of the 442 Viking skeletons indicated two migrations to Scandinavia, both of which took place before and during the Viking Age. As Professor Willerslev explains, these migrations brought Asian and southern European DNA to Scandinavia:

‘The migration from southern Europe passed through what is currently Denmark, and the Asian migration passed through today’s Sweden. DNA analyses of the skeletons paint a picture of a Viking Age Scandinavia with three main centres: Denmark and the two Swedish islands of Øland and Åland. At the time, the rest of Scandinavia was, more or less, what we’d now call the “rotten egg”.’

The scientific article demonstrates that Vikings living in Scandinavia had different preferences when they went on a raid: the “Swedes” tended to head towards the Baltic region, the “Danes” preferred England, and the “Norwegians” were drawn to Ireland, Iceland and Greenland.
One of the Danish researchers responsible for the Nature article, archaeology professor Søren Sindbæk from Aarhus University, explains that the analyses of the many skeletons – found in Viking graves that could be dated – also recount fascinating tales of how local communities set out on raids:

‘At one point, the bones of a group of men from the Viking Age were found in Salme, Estonia, buried in a boat. And when we performed DNA analysis on these bones during the course of our research project, we found that four of the men were brothers.’
Further investigations indicated that the four brothers, who fell in the same battle, probably came from central Sweden. It is not certain what they were doing in Estonia, but they may have been hunting for slaves in eastern Europe.

Several of the bone discoveries on which the Nature article is based show that it was possible to become accepted as a Viking even if you did not have a genetically Scandinavian background. And this is another important find, says Søren Sindbæk:

‘These people were given authentic Viking burials – we know this from the original excavation – but our DNA analyses showed they didn’t have a genetically Scandinavian background. For instance, two Vikings found in Norway were of Sami origin, and another two had been buried on the Orkney islands. They had been laid in their graves with their swords, as was customary for the Vikings, but genetically they were more closely related to the population we see today in Scotland and Ireland. And in both cases, one particular factor seems to be more important than genetics – acceptance of the Scandinavian culture.’

 

Facts:

The title of the scientific article in Nature is: “Population Genomics of the Viking World”.

In addition to numerous Danish scientists from the Technical University of Denmark, Aarhus University and the University of Southern Denmark, among others, researchers from Italy, Poland, Russia, Norway, the UK, Iceland, Taiwan, Estonia, Mexico, Australia, Canada, the USA, Sweden, Armenia, the Faroe Islands, France and Ireland participated in the scientific project.