Modern humans carry Neanderthal DNA fragments due to ancient interbreeding
Sexual selection influenced which Neanderthal DNA was passed down
X chromosomes contain less Neanderthal DNA due to selective inheritance
This selective pattern emerged from mating preferences 46,000 years ago
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Scientists have discovered that sexual selection played a crucial role in determining which Neanderthal DNA fragments were passed down to modern humans, according to research published recently. The study reveals that while most people today carry fragments of Neanderthal DNA in their genome, the distribution of this ancient genetic material was heavily influenced by mating preferences that occurred 46,000 years ago when modern humans first encountered Neanderthals in Eurasia.
The findings suggest that when modern humans migrated out of Africa and met Neanderthal populations, interbreeding occurred but with selective outcomes. While Neanderthal DNA was passed through both male and female lineages, researchers found a distinct pattern on the X chromosome, which is only passed from mothers to their children. This selective inheritance pattern indicates that certain genetic advantages or disadvantages associated with Neanderthal DNA influenced which fragments were preserved in subsequent generations.
The researchers analyzed genomic data from thousands of modern humans to trace the specific regions of Neanderthal DNA that remain in our genome. They discovered that the X chromosome contains significantly less Neanderthal DNA compared to other chromosomes, suggesting that natural selection actively removed certain Neanderthal genetic variants from this particular chromosome. This pattern likely emerged because Neanderthal X chromosomes carried genes that were incompatible with modern human biology or reduced fertility in hybrid offspring.
Humans (Homo sapiens, meaning "thinking man" or "wise man") are the most common and widespread species of primate, and the only extant species of the genus Homo. They are great apes characterized by hairlessness, obligate bipedality, manual dexterity with opposable thumbs, precision grip, and high i...
Mode of natural selection involving the choosing of and competition for mates
Sexual selection is a mechanism of evolution in which members of one sex choose mates of the other sex (intersexual selection) to mate with, and compete with members of the same sex for access to members of the opposite sex (intrasexual selection). These two forms of selection mean that some individ...
The same attraction may have had the opposite effect in societies of modern humans who left Africa 46,000 years ago. Modern human women may have preferred men with Neanderthal ancestry — but those men could pass down a Neanderthal X chromosome to only half their offspring on average. So over time, the X chromosomes of modern humans carried ever less Neanderthal DNA.
