Neanderthal DNA Exists in Humans, But One Piece Is Mysteriously Missing [View all]

Longish article, different explanations are proposed for the missing Y chromosome.
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Genetic studies are revealing ever more about the links between modern humans and these long-gone relatives – most recently that a rush of interbreeding between our species occurred in a relatively short burst of time around 47,000 years ago. But one mystery still remains.

The Homo sapiens genome today contains a little bit of Neanderthal DNA. These genetic traces come from almost every part of the Neanderthal genome – except the Y sex chromosome, which is responsible for making males.

So what happened to the Neanderthal Y chromosome? It could have been lost by accident, or because of mating patterns or inferior function. However, the answer may lie in a century-old theory about the health of interspecies hybrids.

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The missing Neanderthal Y may then be explained by "Haldane's rule". In the 1920s, British biologist J.B.S. Haldane noted that, in hybrids between species, if one sex is infertile, rare or unhealthy, it is always the sex with unlike sex chromosomes.

https://www.sciencealert.com/neanderthal-dna-exists-in-humans-but-one-piece-is-mysteriously-missing