A pair of recent studies that examined the genomes of ancient people living in the Middle East suggests that farming arose more or less at the same time in different regions, Ars Technica reports.
"This so-called Neolithic Revolution transformed human culture, our genomes, and our ecosystems. But the origins of farming have remained a mystery," Ars Technica's Annalee Newitz writes.
In one study that appeared in Science, an international team of researchers sequenced DNA isolated from bones dating back to the Early Neolithic from Iran's Zagros region, where the earliest evidence for farming has been found. This team uncovered evidence of a population that isn't ancestral to European farmers nor contributed much to modern Europeans. Instead, this population separated from Early Neolithic farmers some 46,000 years to 70,000 years ago and is genetically similar to present-day populations in Afghanistan and Pakistan. From this, they conclude that multiple, genetically different populations began farming in southwest Asia
In the other study, which was published in Nature, another team examined DNA obtained from 44 people who lived in the Near East some 12,000 years to 1,400 years before the Common Era. That group reports that these Near East populations derived about half their ancestry from a Basal European lineage, and notes that the first farmers from southern Levant — Israel and Jordan — and from the Zagros Mountains in Iran were strongly genetically differentiated and descended from local hunter-gatherer groups. Both groups then later mixed with Anatolian farmers and European hunter-gatherers and spread, respectively, to East Africa and the Eurasian steppes.
"That farming arose in separate populations seems to suggest a kind of inevitability to the discovery of agriculture. One popular hypothesis is that when humans reach a certain population size, they're destined to start innovating more," Newitz says.
She adds, though, that researchers will likely continue to argue over precisely why people took up farming and raising livestock.