New evidence has shown that 8,500 years ago, Turkish populations forever changed the lives of ancient Europeans—both historically and genetically. However, scientists have been hard-pressed to study exactly what these changes were, as typically they could only extract enough DNA necessary for intensive study from modern subjects.
“It’s a great mystery how present-day populations got to be the way we are today, both in terms of how our ancestors moved around and intermingled and how populations developed the adaptations that help us survive a bit better in the different environments in which we live,” said co-senior author David Reich, professor of genetics at HMS, in a statement. “Now that ancient DNA is available at the genome-wide scale and in large sample sizes, we have an extraordinary new instrument for studying these questions.”
Thanks to new DNA extraction and analysis techniques, researchers can now directly see how natural selection happened in ancient humans by examining their DNA—and have found support for the idea that Europe’s first farmers arrived from Turkey.
“It allows us to put a time and date on selection and to directly associate selection with specific environmental changes, in this case the development of agriculture and the expansion of the first farmers into Europe,” explained Iain Mathieson, a research fellow in genetics at Harvard Medical School and first author of the study.
According to the study, which is published in Nature, the researchers studied the genes of 230 people who lived in Europe, Siberia, or Turkey between 8,500 to 3,000 years ago—allowing them to create the largest collection of genome-wide datasets from ancient human remains to date. These datasets then allowed them to identify specific genes that changed during and after Europe’s transition from hunting and gathering to farming.
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From the Turkish migrants arose changes on or near genes associated with taller height, the new ability to digest lactose as an adult, light skin pigmentation, and blue eye color. Other variants affected fatty acid metabolism, vitamin D absorption, and immunity—which makes sense, according to co-author Wolfgang Haak.
“The Neolithic period involved an increase in population density, with people living close to one another and to domesticated animals,” he said, meaning that changes to immunity were necessary to keep the population healthy.
“Although that finding did not come fully as a surprise,” he added. “It was great to see the selection happening in ‘real time.'”
Besides helping scientists pinpoint how and when these genes came about, they also show that farming was most likely brought into Europe by Turkish migrants.
“From an archaeological perspective, it’s quite amazing,” said co-senior author Ron Pinhasi, associate professor of archaeology at University College Dublin. “The Neolithic revolution is perhaps the most important transition in human prehistory. We now have proof that people did actually go from Anatolia into Europe and brought farming with them. For more than 40 years, people thought it was impossible to answer that question.
“Second, we now have evidence that genetic selection occurred along with the changes in lifestyle and demography, and that selection continued to happen following the transition.”
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Feature Image: Thinkstock
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