alt Hacker NewsI'm reading Proto which is about the Proto-Indo-European language family and it discusses exactly this, where the hunter gatherer nomads of PIE moved from the Caucuses to more farming oriented areas like plains they settled down and also interbred with the local farmers. But, when droughts happened and food got more scarce from farming, many of the farmers in turn became nomads again. The DNA shows this change apparently.
Excellent! That's been on my TBR list for a while. There's a bit about PIE in Lost Worlds, mostly as supporting evidence for movements and connections between ancient (pardon the pun) lost worlds.