A new paper reports on a transect of ancient DNA from Switzerland confirms a lot of things we knew: the transition between the Neolithic and Copper Age saw a shift toward increased “steppe” ancestry which was strongly male mediated. But one section jumped out at me:
The social and family structures, as reconstructed by biological kinship networks, remain the same before and after the arrival of steppe-related ancestry in the region. The predominant social structure in populations buried at the sites investigated in this study must have been a patrilocal society where males stayed where they were born, and females came from more distant living families, a societal dynamic which has been confirmed by stable isotopes…
The late Marija Gimbutas posited, correctly, that Indo-European languages arrived in Europe through the migration of Kurgan builders from the Pontic steppe. She also suggested that they replaced a more peaceful matrifocal farming population. “Old Europe.” It does not seem she was correct on this.
Lawrence Keely’s War Before Human Civilization has an extensive section on the violence that farmers brought to Europe. The data in this paper shows a massive shift from Y chromosome G2 to R1b coincident with the arrival of steppe populations.
I’ll leave to those with more familiarity with archaeology to work out the details, but this is another case of male groups replacing other male groups.