Scientists drew this conclusion, detailed today (May 7) in the journal PLOS Biology, by calculating the length of regions of shared DNA from 2,000 Europeans.
The same technique hasn't been applied to other continents, but people in other parts of the world are just as likely to be closely related, the researchers said.
"In fact, it's likely that everyone in the world is related over just the past few thousand years," said study co-author Graham Coop, a geneticist at the University of California, Davis.
All in the family
For more than a decade, researchers calculated theoretically that all people shared common ancestors fairly recently.
To test that theory, Coop and his colleagues analyzed 500,000 spots on the genome of Europeans, from Turkey to the United Kingdom. To untangle European ancestry, they calculated the length of shared segments of DNA, or the molecules that contain the genetic instructions for life. When two people share a longer stretch of identical DNA, they are likely to share a more recent common ancestor, since over time those gene segments evolve and diversify.
The researchers found that all Europeans shared a common ancestor just 1,000 years ago.
here were also some regional surprises.
For instance, Italians are slightly less related to one another than people from other European countries are to one another, perhaps because Italians have had a large, fairly stable population for a few thousand years.
In addition, people from the United Kingdom are more related to people from Ireland than they are to other people from the United Kingdom. That's possibly because many people have migrated from the smaller country of Ireland to the bigger United Kingdom in the past several hundred years, Coop told LiveScience.
The researchers also showed that people in Eastern Europe were slightly more related to each other than were those in Western Europe.
That may be he signature of Slavic expansion and migrations, such as those of the Huns and the Goths, about 1,000 years ago, said John Novembre, a population geneticist at the University of Chicago, who was not involved in the study.
The new findings are exciting because they allow researchers to trace much more recent human history.
"In the past human geneticists have been able to focus on the types of population movement that have taken place over tens of thousands of years — like moving out of Africa and into Eurasia," Novembre told LiveScience. "They're starting to see population movements that have taken place in the middle ages."
Ghose, Tia. 2013. “Europeans All Closely Related, Gene Study Shows”. Live Science. Posted: May 7, 2013. Available online: http://www.livescience.com/29390-all-europeans-share-recent-ancestors.html