Mainly men and no close family ties. These are some of the results from the first DNA analyses of individuals from the 5th century massacre at the Iron Age ringfort of Sandby Borg on the island of Öland. The study is part of a major study on the development of the Scandinavian gene pool, from Roman times onwards.
The archaeological studies of Sandby Borg on the island of Öland have generated great interest during the last few years. DNA analyses of skeletons from individuals found in the ringfort have now been published for the first time.
The analyses are part of a major international study on the development of the Scandinavian gene pool over the last 2 000 years. The study is led by Stockholm University and comprises researchers from, among others, Linnaeus University and Kalmar County Museum. The study comprises analyses of skeleton parts from several archaeological locations, among them Sandby Borg in the 5th century, but also the warship Kronan, which sank in 1676. Learn more about the DNA study in the fact box below.
It has now been confirmed through DNA analysis that it is a woman.
Eight men and one woman
As for the material from Sandby Borg, the researchers analysed human remains from 15 individuals. The simplest genetic analysis that requires the least amount of DNA is sex determination, and this could be performed for nine of the individuals. The result showed that out of these nine individuals, eight were biological men and one was a biological woman.
“We knew from before that there were many men among the dead. However, there was one skeleton that we were uncertain about. It has now been confirmed through DNA analysis that it is a woman”, archaeology researcher Ludvig Papmehl-Dufay explains.
“It is difficult to draw any conclusions. This far, it seems that there were mostly men and boys among the dead. However, this could be a coincidence as we have only excavated 10% of the site. It is possible, of course, that there were women elsewhere in the ringfort”, Papmehl-Dufay continues.
No close family ties
Seven of the individuals contained enough DNA to make it possible to conduct more in-depth genetic analyses. These analyses showed, for instance, that there were no close family ties between the analyzed individuals.
“There were no close family ties. Not siblings, cousins, or father/son. However, one should not draw too big conclusions from this either since the sample is so small. There may well have been family ties within the ringfort, even though we cannot see this from these seven randomly selected samples”, says Papmehl-Dufay.
Genetic origin in southern Scandinavia
The analysis also showed that the individuals had their genetic origin locally or regionally in southern Scandinavia. The researchers could establish this by making comparisons between the DNA from the Sandby Borg individuals and DNA from modern Scandinavians. In addition to human DNA, they also found bacterial DNA, as one of the studied individuals was infected by diphtheria.
Good representatives for 5th century Scandinavians
Papmehl-Dufay states that the skeleton material from Sandby Borg is extra valuable as the individuals were not buried or cremated, they were just left as they were.
“These individuals constitute a more representative and well preserved sample for Scandinavians of that time than the individuals we find in graves, since the latter were selected by for us unknown criteria and most of them were cremated”, Papmehl-Dufay continues.
The warship Kronan
The researchers also conducted DNA analyses of twelve individuals from the warship Kronan. All twelve were men. No close family ties were found here either. The origins of the twelve crew members cover the entire Swedish kingdom as it looked at the time: southern Sweden, Mälardalen, Norrland, Finland, and the Baltic countries. They represent the entire land area that was Sweden in 1676.
The work to carry out DNA analyses of skeletons from Sandby Borg and Kronan continues. During the upcoming years, the researchers hope to be able to present more results from their studies.
Facts about the DNA study (for which the analysis material from Sandby Borg is part)
Title: "The genetic history of Scandinavia from the Roman Iron Age to the present"
Led by: Ricardo Rodríguez Varela and Anders Götherström from Stockholm University, together with the company Decode in Iceland. Götherström is also an affiliated researcher at Linnaeus University.
Published: in the scientific journal Cell.
The study has looked at the development of the Scandinavian gene pool over the last 2 000 years. In their work, the researchers used as a basis historical and prehistorical genetic material (genome) from material that has been excavated in Scandinavia. This was compared with genomic data from 16 638 contemporary Scandinavians.
The study shows, among other things, that the genetic variation increased during the Viking Age, which indicates that there was a particularly intensive immigration to Scandinavia during this period.