Neanderthal men chose Homo sapiens women: Genetics reveals the sex life of our ancestors

"The result of those encounters between Neanderthals and Homo sapiens is still visible today in the DNA of anyone of non-African descent, who carries between 1% and 4% Neanderthal heritage. But that heritage isn't evenly distributed: there are large areas of the human genome where the Neanderthal trace is completely absent."

"The second hypothesis is that the Neanderthal X chromosome never became established in our genetic makeup because interbreeding occurred primarily between Neanderthal males and Homo sapiens females: the sons of these couples would have inherited the X chromosome from their human mother, not their Neanderthal father."

"This study does the opposite: it looks for traces of Homo sapiens in Neanderthal DNA to infer, for the first time, what those encounters were like. Since the Neanderthal genome was published, the focus of study has been primarily on the influence of Neanderthal."

Approximately 50,000 years ago, Neanderthals and Homo sapiens interbred, leaving 1-4% Neanderthal DNA in non-African modern humans. However, this genetic heritage is unevenly distributed, with large "Neanderthal deserts" appearing throughout the genome, particularly on the X chromosome. A study by researchers at the University of Pennsylvania provides the strongest explanation for this pattern: interbreeding occurred primarily between Neanderthal males and modern human females. This directional mating pattern explains why Neanderthal X chromosomes are largely absent in modern humans, as male offspring would inherit their X chromosome from their human mother rather than their Neanderthal father. The research represents a novel approach by examining traces of Homo sapiens DNA in Neanderthal genomes rather than the reverse.

Read at english.elpais.com