Farming appears to have been spread by migration of populations, says new study.
A new study, led by co-author Thomas, from University College London (UCL), and cited on bbc.com, has found the original first farmers in our human history had a surprising amount of diversity among their DNA.
The research team compare the genomes of skeletal finds across the Middle East, where it is assumed domestication and farming first began, and the DNA analysis is pointing to a mass migration of people as the cause of spreading farming ideas across the region.
The researchers found very different DNA markers between the farmers of the Zagros mountains of Iran and those who helped spread farming west out of what is now Turkey in to the European continent.
Both of these groups lived long what is called the Fertile Valley in today’s Iran, but they DNA analysis indicates they separated sometime between 46,000 and 77,000 years ago.
The debate over whether farming was spread by migrations of peoples or the adoption of new ideas by indigenous populations has continued for years, and the new findings enforce the migration theory.
“Probably the biggest surprise news about this study is just how genetically different the eastern and western Fertile Crescent early farmers were,” offered Thomas.
Co-author on the study, Dr. Garrett Hellenthal, also from UCL, continued, “It had been widely assumed that these first farmers were from a single, genetically homogeneous population. However, we’ve found that there were deep genetic differences in these early farming populations, indicating very distinct ancestries.”
After the invention of agriculture, groups of Middle Eastern farmers migrated and thoroughly mixed with the populations from the surrounding areas, sharing their ideas and collecting the outsiders DNA in the process.
Dr. Thomas told BBC News, “From the archaeology we know that different species were domesticated in different locations around the Fertile Crescent with no particular centre. So either we’ve got different species being domesticated in different locations and then spreading in something like a free trade zone. Or we’ve got independent domestications in different regions.”
Thomas adds cattle were domesticated from a population of about 100 animals, and that makes it difficult to assume they were domesticated on multiple occasions.
The findings from the team can be found in the journal Science.