Recent studies by scientists have shed light on the mystery of the absence of Neanderthal genes in the X chromosome of modern humans, although their presence is recorded in other parts of the genome, reports Hitech.
Despite the fact that Neanderthal genes make up about 1-2% of the genomes of modern Europeans and Asians, this indicates that our ancestors had offspring with Neanderthals.
However, for a long time, scientists were puzzled as to why Neanderthal genetic materials are virtually absent in the X chromosome. This region of DNA was even dubbed the "Neanderthal desert." Previous hypotheses linked this phenomenon to natural selection, suggesting that such genes were incompatible and therefore did not persist.
A recent study proposed a different perspective. Scientists analyzed the genomes of Neanderthals that existed during the period of interbreeding and compared them with the genomes of modern humans.
The results were unexpected: Neanderthal X chromosomes contained 62% more human genes than any other regions of their DNA. This means that the genetics of Homo sapiens penetrated into Neanderthals, while their genes did not transfer to humans.
The researchers concluded that the main flow of genes was from Homo sapiens women to Neanderthal men. Women have two X chromosomes, while men have one. As a result, Neanderthal X chromosomes could not spread widely in the human population.
Thus, there is no need to resort to the theory of harmful genes to explain the "deserts." Neanderthal X chromosomes did not go extinct—they were originally insufficient in the human population.
However, the question remains as to why Neanderthal men chose women who were unsuitable for reproduction, while modern human men avoided Neanderthal women. Scientists have recorded this fact, but the reasons for such choices require further study.
The results of the study were published in the journal Science.
The article "Neanderthal Men Preferred 'Wrong' Women" appeared on the K-News website.
