This guest post is by Roy King, who is a professor of psychiatry at Stanford University and a research colleague of Stanford geneticist and 23andMe scientific adviser Peter Underhill. Roy and Peter have been using genetics to trace the spread of agriculture from the Near East to Europe.
Genetic studies are starting to provide answers to this enduring question. Not only do genetic studies of sheep, goats, cows and wheat demonstrate that the European varieties are subtypes of the species found in the Near East, but data from the human Y chromosome suggest that people currently living in Southern Europe are descended in large part (at least through the paternal line) from the Near East. This suggests, at least for the Mediterranean areas of Europe, that the most probable scenario is that Near Eastern farmers did actually move into Europe, bringing farming with them.23andMe has a Y chromosome marker on its custom chip, rs34126399, which captures the spread of agriculture from the Near East to Europe. The G state at rs34126399 is found in most individuals carrying paternal haplogroup J2a, whose origin can ultimately be traced to Turkey 15,000 to 20,000 years ago. Southern Turkey is the likeliest source for the initial domestication of wheat.