From an excellent, fascinating interview with geneticist David Reich:
The context that lot of my work in the last few years has been focused on, and that I'm tremendously excited about right now, is to try to use genetics from ancient people to understand how people got to be the way they are today biologically. So what we've done in our research group in the last few years is that we've generated data on an absolutely huge number of people.
The paper that we are currently publishing has data from more than 10,000 ancient people from Europe and the Middle East. These individuals are from all over and from all time depths up to 15,000 years ago. So the last 10,000 years, this is the time period when, in Europe and the Middle East, agriculture comes in. It's a very eventful period culturally, it's a period of extreme population growth, when people began to live differently. We can compare the rate of evolution at the beginning of the time period to the end of the time period and it's gotten faster. And not only has it gotten faster, but genetic variants that were under positive natural selection before in some cases switch to negative selection, so it's a period of oscillation of natural selection.
What seems to have happened is that there's cultural change, due to differences in the way people live, with agriculture, living more densely, living with animals, urbanization, other things that are changing, and they are prompting changes in the genome that are resulting in, on average, changes in frequency of the genetic variants that might be useful for people living in these new and differently challenging environments. But if you look at the individual positions that are significant in Europe, they tend to move in the same direction in East Asia, even though the histories are completely independent in this time period.
If that is right, then cultural change, in particular agriculture and urbanization, has caused a sort of convergent evolution across Eurasia, with the same genes being favored in widely separated populations. Which is fascinating.































.jpg)

















.jpg)