There was a paper out late last year that discussed sex ratio effects in the population of Europe. They found that the Neolithic farming immigrants apparently settled as whole families, and were more likely to incorporate females than males from the pre-existing hunter-gatherers. Which sounds reasonable. The analysis looked at the X chromosome, which will have different levels of ancestry from the autosomes if there is sex-biased gene flow. Seems to me that the authors [Amy Goldberg, first author] should have included stats on uniparental markers [mtDNA and Y-chromosomes] as a sanity check, but they did not, for some reason.
They found that the later gene flow from the Pontic Steppes was large and overwhelmingly male, so much so that it couldn’t be modeled by a single event in which the Steppe men complete replaced the local men – no, there had to be further steppe male inflow after that. Interesting, sufficiently so that I wonder whether it’s correct.
The authors suggested this might have involved chariot-borne warriors, but that’s wrong – way too early for chariots. Wagons, men on horseback, possible and likely: no chariots. But when someone says something lie that, you wonder about their general knowledge of prehistoric archaeology – relevant in figuring this out. Actually you don’t wonder.
In an interview, Rasmus Nielsen (not part of the study) said that the Yamnaya men might have spread because they were “more focused on warfare, with faster dispersal because of technological inventions”. Which isn’t crazy. Amy Goldberg suggested that there were other possible explanations – the Yamnaya men could have been more attractive mates than European farmers because they had horses and new technologies, such as copper hammers. Now that is crazy.
First, to be boring about it, copper metallurgy had already been developed [in the Balkans] by the early farmers – they may have done so earlier than in the Middle East. Certainly long before the Yamnaya invasions.The Iceman had a copper axe. Second, the idea that a complete replacement of y chromosomes could be driven by female choice – presumably while the local men stand aside and play video games – is nuts. Sure, it might happen today, but it’s the sort of complex nonsense that could only be embraced by college graduates. Back in the day, the only way those Yamnaya men scooped up the local sheilas was over the dead bodies of the local G2A farmers.