Neanderthal fathers and human mothers were more common in ancient matings

A Science study of three female Neanderthal genomes finds the Neanderthal X chromosome carries about 62% more human DNA than non-sex chromosomes, a pattern a population model interprets as more frequent matings between female Homo sapiens and male Neanderthals than the reverse.

A study published in Science on 26 February analysed genetic material from three female Neanderthals dated to about 122,000, 80,000 and 52,000 years ago and found each carried traces of human ancestry. The researchers report that the Neanderthal X chromosome had, on average, about 62% more human DNA than non-sex chromosomes. Their population model suggests this pattern can be explained if female Homo sapiens mated with male Neanderthals more often than the reverse over several generations. Authors and other geneticists say this offers an example of how behaviour can shape genomes. Key findings: - Modern humans can carry up to about 4% Neanderthal DNA, and parts of the human genome (including much of the X chromosome) are largely devoid of Neanderthal ancestry, called "Neanderthal deserts." - The team examined three female Neanderthal genomes with distant human ancestry dated to roughly 122,000, 80,000 and 52,000 years ago. - The Neanderthal X chromosome contained on average 62% more human DNA than non-sex chromosomes in these specimens. - Most of the human-derived segments on the Neanderthal X chromosome were located in non-protein-coding regions and did not appear to confer obvious advantage. - A population model by the authors indicates the surplus of human DNA on the Neanderthal X is consistent with a bias toward matings between female humans and male Neanderthals, though the causes of such bias are not clear. Summary: The study highlights that asymmetric mating patterns can leave detectable signals in ancient genomes and that behavioural factors may influence genetic exchange between groups. Undetermined at this time.