Study shows Neanderthals’ human blood mostly came from mothers

While it is common knowledge that Neanderthals and humans interbred long ago, a new genetic study shows that for Neanderthals, their human blood came mostly from their family mothers.

This was probably due to differences in what Neanderthal men and women preferred as mates.

A team of researchers at the University of Pennsylvania came to this conclusion by looking at the amount of human and Neanderthal DNA in Neanderthals’ X chromosomes. the study Published in the journal Science on Thursday Researchers suggest this tells us something beyond Neanderthal biology and genetics.

“This allows us to say something about the social behavior of these ancient populations,” said Sarah Tishkoff, professor of genetics and biology and head of the laboratory that conducted the analysis.

Modern humans originated in what is now Africa, while Neanderthals lived in Europe and Asia. They encountered each other and interbred several times, leaving each other’s genes in their genomes. That’s why all humans with ancestors outside sub-Saharan Africa have some Neanderthal DNA.

Similarly, there is some human DNA in the Neanderthal genome after a period of interbreeding with humans 250,000 years ago.

But it is not spread evenly through their genes and chromosomes.

Extra human DNA in Neanderthal X chromosomes

In this particular study, researchers took a closer look at the The researchers compared the X chromosomes of three ancient Neanderthal women (who each have two

They found that Neanderthal women’s

Alexander Platt, a senior research scientist and evolutionary biologist in Tishkoff’s laboratory, came up with some possible explanations.

One option was that human genes on the X chromosome worked better in Neanderthals than Neanderthal genes and replaced them. If this were the case, there would be more human DNA in regions of the chromosome containing important genes.

“We didn’t find that,” Platt said. In fact, there was more human DNA in parts of the genome “that aren’t really doing anything.”

Another possible explanation is that mating between men with more Neanderthal ancestry and women with more human ancestry was more common than the reverse.

This would result in there being more human DNA in the Women pass X chromosomes to all of their children, while men pass X chromosomes only to their daughters.

Were hybrid men or women… more attractive?

The team found that such unequal pairing – and unequal passing of the X chromosome – could explain what they found.

Then they tried to invent ways by which such unequal pairings could be made.

Platt said, “A very simple thing… if there is a preference that physically modern human lineages are more attractive when found in women than when found in men.”

“Or vice versa, Neanderthal ancestry results in a more attractive individual when it is found in men than when it is found in women.”

Different migration patterns for single men and women do not provide a complete explanation, as unequal pairings will persist for many generations.

The researchers said there may actually be a combination of factors that led to the biases seen in Neanderthal X chromosomes — including mate preferences, different migration patterns between men and women, and natural selection through certain types of genes.

Damien LaBuda, a retired professor at the University of Montreal, has used some of the human genetic datasets collected by Tishkoff in his research. he already got Presence of Neanderthal DNA on the human X chromosome.

LaBuda called the new study “fascinating.”

He said the explanation makes sense and does not exclude the possibility that other factors may influence reproductive patterns, or that multiple factors may work together.

He pointed to recent research suggesting that Neanderthal-human hybrid mothers were Less likely to have a healthy babyDue to the mismatch between the oxygen carrying capacity of the red blood cells of humans and Neanderthals.

Another, earlier study suggested that Neanderthal-human hybrid males were not very fertileBased on the fact that in humans, there are no Neanderthal genes in the part of the X chromosome associated with the testicles.

LaBuda said that ancient Neanderthals may have realized that certain types of pairings resulted in less healthy children and may have shaped their mating preferences or even taboos as a result.

“These people were very good observers. Their intelligence was like ours, so they must have seen things like this happen.”