Research led by geneticist Sarah Tishkoff’s lab finds that prehistoric mating preferences is a likely explanation for why modern humans have so little Neanderthal DNA on their X chromosomes, challenging the idea that human evolution was driven solely by survival of the fittest.
Key Takeaways
- Most modern humans with non-African ancestry carry small amounts of Neanderthal DNA across much of their genome but have little-to-none on their X chromosomes.
- New research from Penn challenges an old assumption that the cause was natural selection and a weeding out of ‘toxic’ Neanderthal genes.
- The researchers found that Neanderthals have more human DNA on their X chromosomes than elsewhere in their genomes.
- Because males and females pass on X chromosomes differently, this genetic pattern, they found, points to a strong sex bias: preferential mating between Neanderthal males and human females.
- Their findings reveal the role of social interactions in human evolution—rather than just biological survival—in sculpting the human genome, challenging the idea that our evolution was driven solely by survival of the fittest.
