The introduction of a farmer's life changed Europeans forever, down to their DNA's very structure.
Since early humans were essentially nomadic hunters, scientists have tried to understand how humans could have adapted to the change in lifestyle that occurred at least about 8,500 years ago. A team of researchers thought of looking for answers in ancient man's DNA.
"It allows us to put a time and date on selection and to directly associate it with specific environmental changes," said Iain Mathieson, a researcher from Harvard Medical School and one of the study's authors.
With more advanced DNA extraction techniques and information taken from the largest collection of genome database from ancient humans, the team found specific genetic changes that occurred during and after humans transitioned from foraging and hunting to farming. The ability to look into DNA so closely enabled the team to look into ancient DNA's complex structure for the first time.
The DNA came from ancient human remains of more than 200 humans who were thought to have lived in different areas of Europe, Turkey and Siberia between 3,000 to 8,500 years ago.
Many of the changes occurred on or near the genes associated with height, fatty acid metabolism, skin pigmentation, vitamin D levels and the ability to digest lactose even during adulthood.
Other changes were noted on genes associated with the immune system, something the researchers noted to have been an additional adaptation to living with a higher population density community that can be expected from early farming villages.
The findings also supported the idea that the first European farmers came from ancient Anatolia, now known as Turkey.
"It's a great mystery how present-day populations got to be the way we are today," said David Reich, professor of genetics at Harvard Medical School and one of the senior co-authors of the study. Reich added that they have yet to learn how human ancestors moved about, how they eventually dwelled into settlements and how they developed the survival skills needed in their new environments.
Archeologists also found the research to have significant paleontological impact, as it gave proof that ancient humans did travel to Europe from Anatolia and started farming in their arrival. The study's findings also provided evidence that natural selection happened along with lifestyle and geographical changes.
The researchers' findings are published in the journal Nature.