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Prehistoric teeth discovered at a Jersey site reveal signs of interbreeding between Neanderthals and our own species, scientists say.
British experts have re-examined 13 teeth found between 1910 and 1911 at La Cotte de St Brelade, in the south-west of the island.
They have long been considered typical Neanderthal specimens, but re-evaluation also revealed features characteristic of modern human teeth.
The teeth may represent some of the last known Neanderthal remains.
As such, they might even give clues as to what caused the demise of our evolutionary close cousins.
Neanderthals evolved around 400,000 years ago and inhabited a large area from Western Europe to Siberia.
They were generally shorter and stockier than modern humans, with a thick bony crest hanging over the eyes.
They eventually disappeared around 40,000 years ago, just like anatomically modern humans (homo sapiens), a species newly arrived from Africa, settled in Europe.
However, the two types of humans can overlap for at least 5,000 years.
The teeth were discovered on a small granite ledge at the cave site.
They were previously thought to belong to a single Neanderthal individual. However, new research found they were from at least two adults.
Researchers used computed tomography (CT) scans of teeth to study them at a level of detail that was not available to researchers in the past.
“Double ancestry”
Although all specimens have Neanderthal characteristics, some aspects of their shape are more typical of the teeth of modern humans.
This suggests that these were traits that were prevalent in their population.
Research director Professor Chris Stringer, Natural History Museum, London, said: “Since modern humans rode Neanderthals in parts of Europe 45,000 years ago, the unusual characteristics of these individuals from La Cotte suggest that they may have had a double Neanderthal. modern human ancestry. “
When these individuals were alive, the climate in this part of the world was colder than today, and the sea level was several tens of meters lower.
Co-author Dr Matt Pope, from the Institute of Archeology at University College London (UCL), said the area would have been “fantastic for hunting”, due to its “dead end valleys and of its blind ravines “.
“Caves of this scale and size are extremely rare in this landscape,” he said, adding, “It seems to be built into their routines, coming back to this place for tens of thousands of years.”
In fact, there is a record of occupancy at the La Cotte site dating back 250,000 years.
Human teeth are thought to be around 48,000 years old, which is close to the presumed Neanderthal extinction date of 40,000 years ago.
So, rather than disappearing in the traditional sense, were the Neanderthal groups simply absorbed by the incoming modern human populations?
“This must now be a seriously considered scenario, alongside others, and it will emerge as we gain a better understanding of the process of genetic mixing,” Dr Pope told BBC News.
“But certainly that word ‘extinct’ is now starting to lose its meaning where you can see multiple episodes of mixing and retention of a significant proportion of Neanderthal DNA in humans beyond sub-Saharan Africa.”
Neanderthals contributed 2-3% of the genomes – the book of genetic instructions for making a person – of people of non-African ancestry.
“This idea of a hybrid population could be tested by recovering ancient DNA from teeth, something which is currently under investigation,” said Professor Stringer.
The study was published in the Journal of Human Evolution.
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