Discovery of ancient sheep DNA alters origin story of alleged Viking settlement

Nick Balascio and other members of a research team dig Lake Eidisvatn on the Faroe Islands, taking long tubes of sediment from the bottom of the lake to bring back to the lab for analysis. (Photo by Raymond Bradley, University of Massachusetts Amherst)

WILLIAM & MARY – The Faroe Islands, an archipelago between Norway and Iceland, are believed to have once been settled by Viking explorers in the mid-9th century CE. Thanks to a new analysis of the ancient DNA of sheep, it is now shown that remote islands in the North Atlantic were inhabited by British shepherds centuries before the arrival of the Vikings.

“Until recently the prevailing theory was that the Faroe Islands were first settled by the Vikings during their westward migrations across the North Atlantic to the British Isles and then to Iceland and Greenland” , said Nick Balascio, associate professor of geology at William & Mary, who was part of a team of scientists studying biogeochemical markers left in lake sediments to map environmental changes and reconstruct patterns of human activity on islands. “Using sedimentary DNA and molecular biomarkers, we were able to establish more firmly when human presence began on the islands – and this was at least 300 years earlier than previously thought.”

Nick Balascio, associate professor of geology at William & Mary, was part of a team of scientists studying biogeochemical markers left in lake sediments to reconstruct patterns of human activity on the Faroe Islands. (Photo by Joseph McClain/W&M News)

Balascio is co-author of a study recently published in Nature: Communications Earth and environment which used a combination of sedimentary DNA and biomarkers produced in the digestive tract of sheep, faecal biomarkers, to show conclusive evidence that humans had introduced cattle to the Faroe Islands three to four centuries before the Norse colonization period of the Viking Age documented in the existing archaeological disk.

He explained that the islands represent an important “stepping stone” in the westward migration of Scandinavian and Hiberno-Nordic peoples to Iceland, Greenland and beyond. The timing of colonization has greater significance in understanding the history of human exploration and colonization, he added.

“We knew that when people first showed up on the islands, because they were uninhabited, we should be able to see the impacts of the changes they were making to their environment, especially through the introduction grazing animals,” Balascio said.

By analyzing hundreds of years of soil layers deposited on island lakes, Balascio and his co-authors were able to find traces of ancient DNA or other molecular evidence that they say “unequivocally identifies the signature of human presence on the Faroe Islands”.

“In a broad sense, we were looking for signatures in these lake sediments that showed people were in the landscape,” Balascio said. “But in practice, it’s actually hard to do. We can’t necessarily see human DNA, because there weren’t enough concentrations of people living in a watershed that would drain into a lake. What we found was a large amount of sheep DNA in a lake watershed.

The discovery of sheep sedimentary DNA provides evidence that humans introduced cattle to the Faroe Islands centuries before the Viking Age period of settlement documented in extant archaeological records. (Photo by Raymond Bradley/UMass Amherst)

Balascio and his co-authors first came up with the idea to analyze lake sediments from the Faroe Islands after a 2013 paper announced the discovery of charred barley grains at an archaeological site on the island of Sandoy. , prior to Viking colonization.

“It seemed like a question we could really tackle with our expertise,” Balascio said. “We came in thinking that we could use the lake sediments, which are continually accumulating material during this time interval, to try to date when people showed up.”

The team of scientists from William & Mary, University of Massachusetts and Columbia University specialize in paleoclimatology, using new molecular techniques to reconstruct the past history of environmental change. For this study, the team also collaborated with DNA specialists from the Palaeogenomics Laboratory at the University of California, Santa Cruz.

Funding for the project was provided by a collaborative grant from the Division of Behavioral and Cognitive Sciences of the US National Science Foundation to William & Mary, University of Massachusetts Amherst, and Columbia University.

“Over the past few years, we have begun to understand more and more the impacts that humans have on landscapes as they begin to establish agricultural colonies that eventually grow into larger civilizations,” Balascio said. “We realized that we had these tools that reconstruct past environments and that we could use them to answer more anthropological questions about where people were and how they lived in certain environments over time.”

In this case, the team analyzed molecular remains to determine that there were shepherds, probably from the British Isles, grazing their cattle on the Faroe Islands from 500 AD, even before the Vikings had maritime technology to make the trip to the islands. They also used lake sediments to provide a detailed history of subsequent vegetation changes as a result of human arrival and land use.

Before the sediments can be studied in the laboratory, a field team is responsible for coring the lakes, taking long tubes of sediment from the bottom of the lake. The central tubes are lowered down the sides of inflatable rafts with ropes, filled with sediment and brought up from the depths.

Back at the William & Mary lab, Balascio and his students analyzed the samples in an attempt to piece together a historical record where none existed, dating the deposits in the sediments using radiocarbon and volcanic ash from Icelandic eruptions.

“With this type of work, one of the most important things is chronology – how well we know about time – and Icelandic volcanic eruptions can be used to actually date sediments,” Balascio explained. One of his undergraduate students, Genevieve Pugsley ’18, was a key member of the research team developing the volcanic ash chronology and co-authored a previous publication based on the lake sediment record.

“One of the main obstacles to assigning earlier settlements on remote islands like these is the lack of physical archaeological data,” Balascio said. “With this kind of limited evidence, we need to get creative and develop new interpretations and methods to understand and limit time.”

Always be informed. Click here to get the latest news and information delivered to your inbox

Back To Top