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SYDNEY: The first peoples to farm Europe were not the hunter-gatherers that roamed the continent more than 8,000 years ago, but Middle Eastern populations that moved in, according to a study of ancient DNA.
The research helps to resolve longstanding disagreement between two conflicting theories on the advent of farming in Europe: the cultural diffusion model where technology spread through interbreeding and the demographic flux model involving expansion of existing farming cultures.
"We have finally resolved the question of who the first farmers in Europe were - invaders with revolutionary new ideas, rather than Stone Age hunter-gathers who already existed in the area," said lead author Wolfgang Haak, from the Centre for Ancient DNA (ACAD) at the University of Adelaide, South Australia, whose study was published PLoS Biology.
A farming invasion
The first farming communities in Europe, who lived in central Germany and were known as the Linear Pottery Culture, began demonstrating sedentary farming practices around 8,000 years ago, 3,000 years after it was first seen in the Fertile Crescent, in today's Middle East and Turkey.
"[Previous] thinking accepts that the first European farming populations were constructed largely from existing populations of hunter-gatherers," said Alan Cooper, director of the ACAD and project leader for the study.
Until now, it was thought that these hunter-gatherers developed farming as a result of cultural and social defusion from the Middle East as people from the region intermingled and bred with the European populations. But this new study contradicts the theory.
Constructing the past
"We have been able to use genetic signatures to identify a potential route from the Near East and Anatolia, where farming evolved around 11,000 years ago, via a south-eastern Europe and [Hungary] into Central Europe," said Haak.
The ancient DNA used in the study came from skeletons excavated from a complete graveyard of Early Neolithic farmers unearthed from Derenburg, a town in central Germany. "[This] dataset provides the most detailed and direct genetic portrait of the Neolithic transition in Central Europe," said the authors.
"We've been able to apply new, high-precision ancient DNA methods to create a detailed genetic picture of this ancient farming population, and reveal that it was radically different to the nomadic populations already present in Europe," said Haak.
The origins of farming
The biggest problem was getting the skeletons out of the ground and into the lab without contaminating them with modern human DNA. "[It] was only possible due to close collaboration of the archaeologists excavating the skeletons … [with] the geneticists," said Kurt Alt from the collaborating Institute for Anthropology in Mainz, Germany.
"Ancient DNA can be problematic due to issues with contamination but these guys have done [excellent research]," said James Haile, an ancient DNA expert at Murdoch University, Perth, Western Australia who wasn't involved in the study.
"The idea's very interesting," said Haile. "It certainly adds weight to the genetic movement as opposed to a social diffusion of farming practices through Europe."
more information please
So what is this telling us?
The genetic information from one area... is it;
-comparable to modern European populations
-comparable to modern Middle Eastern populations
-proof that there was or was not any exchange of genetic information between groups outside of this one area.
-None of the above.