Farming Began in Two Separate Places in the Mideast
Ancient genomes reveals two different groups independently developed agriculture.
Photo: The Fertile Crescent and the Middle East, seen from space. Credit: NASA The reason that you're able to sit in a comfortable chair in your home and read this article on your tablet or laptop is that many thousands of years ago, humans shifted from being nomadic hunter-gatherers to raising their own food crops and domesticating animals. That breakthrough enabled our species to stay in one place long enough to build villages, towns and cities, and to start developing the technologies that eventually led to the advanced civilization we have today.
But who actually was the first to invent farming? A new genetic study suggests that two different groups of people in the Middle East independently developed agriculture, and then gradually spread their practices to Europe, Africa and Asia.
In the study, which recently was published online at Biorxiv.org, researchers looked at the genomes of 44 individuals who lived between 3,500 and 14,000 years ago in present-day Armenia, Turkey, Israel, Jordan and Iran. The difficult-to-obtain ancient DNA was extracted from a tiny ear bone -- called the petrous -- by a team led by Losif Lazaridis and David Reich, two population geneticists at Harvard Medical school.
The team found stark differences between the genomes of ancient people on the southern side of the region in Israel and Jordan, and those on the other side of the Zagros mountains in western Iran. That pattern is consistent with existing evidence that the two groups didn't mingle, and separately developed the ability to grow crops.
"There has been a school of thought arguing that everything happens first in the southern Levant and everyone learns how to be farmers from this initial dispersal," Roger Matthews, an archaeologist at the University of Reading, U.K., who co-directs the Central Zagros Archaeological Project in Iran, explained in a Nature.com article. "But the archaeological evidence shows very strong local traditions that are clearly not in communication with each other, persisting for centuries if not millennia."
Agriculture seems to have developed about 11,000 years ago in those places. The two groups also focused on different agricultural products, with the southern farmers domesticating goats and growing cereals such as emmer, while the western group cultivated barley and wheat.
About 9,500 years ago, the two populations of farmers finally may have mixed in eastern Turkey, where they probably were searching for sources of obsidian, which they needed to make tools. By the time farmers from Turkey began migrating to Europe, they had what the researchers call a "Neolithic Toolkit," which included crops, animals and tools from both farming traditions.
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