New DNA analysis suggests that several distinct hunter-gatherer populations independently adopted farming in the Fertile Crescent in Neolithic times.
From there, these pioneers fanned out towards Europe in the west and east towards what is now Iran, Afghanistan and beyond.
The findings appear to run counter to earlier assumptions that Neolithic populations, which switched from hunting and gathering to agriculture some 10,000 years ago, were homogeneous.
Researchers sequenced the genomes of skeletons of the remains of early Neolithic farmers in the Zagros region of Iran, bordering Iraq.
They discovered that the individuals were of a previously uncharacterised population, and not the ancestors of European farmers, who were thought to have originated in Anatolia, now Turkey.
Instead these Zagros farmers split off from that Anatolian genome, the researchers write in the paper published in Science: “These people are estimated to have separated from Early Neolithic farmers in Anatolia some 46-77,000 years ago and show affinities to modern Pakistani and Afghan populations.”
“We know that farming technologies, including various domestic plants and animals, arose across the Fertile Crescent, with no particular centre,” co-author Mark Thomas, of University College, London, says.
“But to find that this region was made up of highly genetically distinct farming populations was something of a surprise.”
The individuals would have looked different, and spoken different languages from their counterparts in Anatolia, he says.
“It seems like we should be talking of a federal origin of farming.”
For such a significant development in human history relatively little is known about how agriculture originated and spread into neighbouring regions such as Europe, North Africa and southern Asia.
Co-author Stephen Shennan of UCL says the current study adds significantly to that debate.
“We’ve shown for the first time that different populations in different parts of the Fertile Crescent were coming up with similar solutions to finding a successful way of life in the new conditions created by the end of the last Ice Age,” he says.
Bill Condie is a science journalist based in Adelaide, Australia.
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