In the Iberian peninsula — modern Spain and Portugal — the Yamnaya genetic impact is smaller than in Germany and Britain, about 40 percent, but the Y chromosome of the first farmers who preceded them is entirely absent in the population, a sign of something that “can’t have been a happy occasion for the men involved,” Reich said.“The local male population completely failed to transmit its Y-chromosomes to the subsequent population,” Reich said. “How that happened, we don’t know, but several thousand years later, the descendants of these Iberians came to the Americas and exactly this happened. People in Colombia have almost no local Y-chromosomes. They’re almost all European. And they have almost no European mitochondrial DNAs (inherited through the mother). They’re almost all Native American. And that’s the result of exploitation and social inequality. And perhaps that’s what occurred here.”
I doubt they got friend-zoned. The dudes were probably killed/enslaved.
“The big perspective change from ancient DNA study is that people living today are almost never the descendants of the people in the same place thousands of years before,” Reich said. “Human movements have occurred at multiple timescales, often disruptive to the populations that experience them, and these patterns were not possible to predict and anticipate without direct data.”
Reich said it had been believed that natural selection was minimal among humans for the last 10,000 years, and his own early study, in 2015, showed just a dozen places in the genome that had changed over the last 8,000 years in a way that might indicate natural selection.Last year, a similar study showed 21. So Reich and his team set out to develop ways to reduce false signals and increase statistical power. In an examination of 10,000 people’s genomes, they found almost 500 significant changes.Reich now believes Europe, at least, is in a period of accelerated selection that began 5,000 years ago, focusing on immune and metabolic traits. Some traits show up in the DNA record as rising over time and then plummeting, as with genes that make one prone to celiac disease and a severe form of tuberculosis.
It makes sense that we're evolving the systems that are under selection pressures still. We're definitely ill-adapted to modernity in other ways (e.g. sitting all day), but it doesn't kill us before producing offspring so we might never adapt to it.