Today's Scandinavians are not descended from the people who came to Scandinavia at the conclusion of the last ice age but, apparently, from a population that arrived later, concurrently with the introduction of agriculture. This is one conclusion of a new study straddling the borderline between genetics and archaeology, which involved Swedish researchers and which has now been published in the journal Current Biology.

"The hunter-gatherers who inhabited Scandinavia more than 4,000 years ago had a different gene pool than ours," explains Anders Götherström of the Department of Evolutionary Biology at Uppsala University, who headed the project together with Eske Willerslev of the Centre for GeoGenetics at the University of Copenhagen.

The study, a collaboration among research groups in Sweden, Denmark and the UK, involved using DNA from Stone Age remains to investigate whether the practices of cultivating crops and keeping livestock were spread by immigrants or represented innovations on the part of hunter-gatherers.

"Obtaining reliable results from DNA from such ancient human remains involves very complicated work," says Helena Malmström of the Department of Evolutionary Biology at Uppsala University.

She carried out the initial DNA sequencings of Stone Age material three years ago. Significant time was then required for researchers to confirm that the material really was thousands of years old.

"This is a classic issue within archaeology," says Petra Molnar at the Osteoarchaeological Research Laboratory at Stockholm University. "Our findings show that today's Scandinavians are not the direct descendants of the hunter-gatherers who lived in the region during the Stone Age. This entails the conclusion that some form of migration to Scandinavia took place, probably at the onset of the agricultural Stone Age. The extent of this migration is as of yet impossible to determine."