Study results show most Europeans evolved from a common ancestor
WASHINGTON (AP) About 80 percent of Europeans arose from primitive hunters who arrived about 40,000 years ago, endured the long ice age and then expanded rapidly to dominate the continent, a new study shows.
Researchers analyzing Y chromosomes of 1,007 men from 25 locations in Europe found a pattern that suggests four of five of them shared a common male ancestor about 40,000 years ago.
Peter Underhill, a senior researcher at the Stanford University Genome Technology Center and co-author of the study, said the research supports conclusions from archaeological, linguistic and other DNA evidence about the settlement of Europe by ancient peoples.
"When we can get different lines of evidence that tells the same story, then we feel we are telling the true history of the species," said Underhill.
The study, co-authored by Underhill and more than a dozen researchers from Stanford and Europe, appeared Friday in the journal Science.
Underhill said the researchers used the Y chromosome in the study because its rare changes establish a pattern that can be traced back hundreds of generations, thus helping to plot the movement of ancient humans.
The Y chromosome is inherited only by sons from their fathers. When sperm carrying the Y chromosome fertilizes an egg, it directs the resulting embryo to be male. An X chromosome from the father allows a fertilized egg to be female.
The Y chromosome has about 60 million DNA base pairs. Changes in the pairs happen infrequently, said Underhill, but often enough to establish patterns that can be used to trace the ancestry of people.
He said researchers looking at the 1,007 chromosome samples from Europe identified 22 specific markers that formed a specific pattern of change. Underhill said that the researchers found that about 80 percent of all European males share a single pattern, suggesting that they had a common ancestor thousands of generations ago.
Underhill said the basic pattern had some changes that apparently developed among people who once shared a common ancestor and then were isolated for a long time.