Europe is all just one big family: study

From Ireland to the Balkans, Europeans are basically one big family, closely related to one another for the past thousand years, a new study has found.
DNA analysis of people from across the continent found that Europeans likely share a common ancestor from as recently as 1,000 years ago.
"What's remarkable about this is how closely everyone is related to each other. On a genealogical level, everyone in Europe traces back to nearly the same set of ancestors only a thousand years ago," said Graham Coop, professor of evolution and ecology at the University of California, Davis.
"This was predicted in theory over a decade ago, and we now have concrete evidence from DNA data," Coop said, adding that "such close kinship likely exists in other parts of the world as well."

Coop and co-author Peter Ralph, now professor at University of Southern California, set out to study relatedness among Europeans in recent history, up to about 3,000 years ago.
They compared genetic sequences from more than 2,000 individuals.

Researchers found that the degree of genetic relatedness between two people tends to be smaller the farther apart they live.
But even a pair of individuals who live as far apart as the UK and Turkey - a distance of some 3219 km - likely are related to all of one another's ancestors from a thousand years ago.
Subtle local differences, which likely mark demographic shifts and historic migrations, exist on top of this underlying kinship, Ralph said.

Barriers like mountain ranges and linguistic differences have also slightly reduced relatedness among regions.
Coop noted, however, that these are all relatively small differences.
"The overall picture is that everybody is related, and we are looking at only subtle differences between regions," he said.
To learn about these patterns, researchers used ideas about the expected amount of genome shared between relatives of varying degrees of relatedness.
Ralph and Coop looked for shorter blocks of DNA that were shared between cousins separated by many more generations.
Because the number of ancestors doubles with every generation, the chance of having identical DNA in common with more distant relatives quickly drops.

But in large samples, rare cases of distant sharing could be detected. With their analysis, Coop and Ralph were able to detect these shared blocks of DNA in individuals spread across Europe, and calculate how long ago they shared an ancestor.
The study was published in the journal PLoS Biology.