Stone Age teeth indicate Neanderthals interbreeding

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During this time Homo sapiens and Neanderthals met and sometimes had sex and gave birth to children. The evidence is hidden in our genes, DNA analysis has shown, with most Europeans having about 2% Neanderthal DNA in their genomes from this ancient cross.

However, there is relatively little direct physical evidence of these encounters and fossilized bones. Found skeletons have not provided definitive proof.

Now, a new analysis of 11 teeth found in a cave in Jersey, an island in the English Channel, has suggested that some of them belonged to individuals who had Homo neanderthalensis and Homo sapiens ancestors.

The teeth, identified as Neanderthal, were found when the site, known as La Cotte de St. Brelade, was first excavated in 1910 and 1911. A new analysis of the teeth, published in the Journal of Human Evolution on Monday, has demonstrated that the helicopters actually came from two different individuals who lived there 48,000 years ago. Seven of the teeth had both modern human and Neanderthal features.
Since the first stone tools were discovered in La Cotte in 1881, other discoveries followed, such as the teeth. The site was first excavated in 1910 and 1911.

“We find the same unusual combinations of Neanderthals and modern human traits in the teeth of both identified Neanderthals,” said the study’s author. Chris Stringer, research leader in human origins and professor at the Natural History Museum in London.

“We consider this the strongest direct evidence to date (of hybridization) found in fossils, although we don’t have any DNA evidence to support this yet,” he said.

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The team tried to extract DNA from the teeth to confirm whether the teeth belonged to individuals with dual Neanderthal-modern human heritage, Stringer said. Retention of DNA was “a matter of chance,” given the age of the teeth, he explained.

“The tooth roots look very Neanderthal, while the necks and crowns of the teeth are much more like those of modern humans,” he said.

The only other explanation, he said, was that this population was extremely geographically isolated and developed these unusual features in their teeth.

It could be that this (is) a highly unusual population that developed this combination of features in isolation – but at this time, due to the lower sea levels of the last Ice Age, Jersey was certainly linked to neighboring France, so isolation is unlikely, ”he explained via email.

It was surprising to find this evidence of “hybrid” individuals with the ancestors of Neanderthals and Homo sapiens in northwestern Europe, he said, because the earliest evidence of early modern human influence is found much further east in Europe. Evidence in present-day Bulgaria may date back 47,000 years, and in Iberia and southern France 42,000 years ago.

Likewise, the fossil evidence of crossing has also been found further east.

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The most definitive case is of the Oasis Cave in Romania, where a 40,000-year-old jawbone was excavated, with unusual features. Genetic analysis found that it contained 9% Neanderthal DNA, from crossing that likely took place in the previous five generations, Stringer said.

A 50,000-year-old bone fragment discovered in a Russian cave in 2018 represented the first known remains of a child with a Neanderthal mother and a Denisovan father – another extinct relative of modern humans believed to be predominantly in Asia.

Teeth are especially important to archaeologists and paleoanthropologists because they are stronger than bones. The glaze is already largely mineralized and no longer organic, so it can survive very well in the fossil record.

The La Cotte site in Jersey shows that Neanderthals used the cave for as many as 200,000 years, the Natural History Museum said, with the Earth’s layers being repeatedly reoccupied by various Neanderthal groups and at least two mounds of mammoth bones.

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