A recent genetic study suggests that Neanderthals mainly inherited modern human DNA from the female members of their population due to mate preferences. Researchers at the University of Pennsylvania reached this conclusion by analyzing the levels of “anatomically modern human” (AMH) and Neanderthal DNA in Neanderthal X chromosomes. This study, published in the journal Science, sheds light on the social behaviors of ancient populations.
The research indicates that while modern humans originated in Africa and Neanderthals resided in Europe and Asia, interbreeding between the two groups occurred multiple times, resulting in the presence of Neanderthal DNA in non-African human ancestry. Notably, Neanderthal genomes show traces of human DNA, albeit not uniformly distributed across their genetic makeup.
The study focused on the X chromosome, which men possess only one of, unlike other chromosomes present in pairs. By comparing the X chromosomes of ancient Neanderthal women with those of modern human women from sub-Saharan Africa, researchers observed significantly higher levels of human DNA in Neanderthal X chromosomes compared to their autosomes.
Possible explanations proposed by the research team include the theory that human genes on the X chromosomes outperformed Neanderthal genes and gradually replaced them, leading to the observed genetic patterns. Unequal pairing and the differential inheritance of X chromosomes between men and women could also contribute to the prevalence of human DNA in Neanderthal X chromosomes.
The study suggests that preferences in mate selection, migration patterns, and natural selection may have collectively influenced the genetic composition of Neanderthal X chromosomes. These findings offer insights into the interbreeding dynamics between Neanderthals and modern humans and provide a deeper understanding of ancient populations’ social dynamics.