A quarter of the prehistoric farmers were found to share a mitochondrial DNA signature that is now extremely rare worldwide and has left virtually no trace on living Europeans.
The apparent failure of these people to make their genetic mark stands in stark contrast to farming itself, which spread rapidly across Europe.
A possible explanation, the researchers write in their study, is "that small pioneer groups carried farming into new areas of Europe, and that once the technique had taken root, the surrounding hunter-gatherers adopted the new culture and then outnumbered the original farmers."
Cambridge's Forster added, "It's interesting that a potentially minor migration of people into central Europe had such a huge cultural impact."
Archeologist Marek Zvelebil agrees, saying the DNA findings support evidence from pottery and other artifacts from the beginning of the Late Stone Age.
"This is one of the first studies to actually examine the bones of ancient human beings who lived 7,000 to 8,000 years ago," said Zvelebil, a professor at the University of Sheffield, England.
"Archaeological evidence indicates that what we had was cultural diffusion and a mixture of perhaps some immigration and local adoption of farming culture," he added. "There's been 30 years of debate about this pointhow the farming way of life reached Europe and spread.
"Small groups of people migrated from the Near East into parts of the East Mediterranean and central Europe. But in most other parts of Europe you had local hunter-gathering people adopting farming."
Other researchers are less certain about this theory, saying the farmers' male genetic materialknown as Y-chromosome sequencesneeds to be established first.
They argue that colonizing male farmers might have taken up with indigenous European women, in which case mitochondrial DNA traces of their lineage could have been largely erased over time.
Bentley of Durham University says this theory may hold true in part.
"In many historical instances men in colonizing populations have intermarried with indigenous women," he said.
Yet evidence from elsewhere in Europe supports the idea that the introduction of farming represents a cultural rather than a genetic exchange, according to David Miles, research fellow at the Institute of Archaeology in Oxford, England, and author of the book, The Tribes of Britain.
"In northwest Europe the genetic evidence suggests [farming] came mainly as an idea and that the number of people moving was relatively small," Miles said.
Most of the farmers in Britain, for instance, would have been native descendents of the hunter-gatherers, he said.
"There's been a lot of arguing over the last ten years, but it's now more or less agreed that about 80 percent of [modern British] genes come from a very small number of hunter-gatherers who came in immediately after the Ice Age," he said.
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