Prehistoric teeth excavated at a site in Jersey reveal signs of interbreeding between Neanderthals and our own kind, scientists say.
British experts have re-examined 13 teeth found between 1910 and 1911 in La Cotte de St Brelade in the southwest of the island.
They were long considered typical Neanderthal specimens, but the reassessment also revealed features characteristic of modern human teeth.
The teeth may represent some of the last known Neanderthal remains.
As such, they can even provide clues as to the cause of the disappearance of our closest evolutionary cousins.
The Neanderthals evolved about 400,000 years ago and inhabited a wide area from Western Europe to Siberia.
They were generally shorter and stockier than modern humans, with a thick rim of bone hanging over the eyes.
They eventually disappeared about 40,000 years ago, just like anatomically modern humans (homo sapiens), a newly arrived species from Africa, settled in Europe.
However, the two types of people can overlap for at least 5,000 years.
The teeth were discovered on a small granite ledge near the cave.
They were previously thought to belong to a single Neanderthal. However, the new research found that they came from at least two adults.
The researchers used computed tomography (CT) scans of the teeth to study them at a level of detail not available to researchers in the past.
‘Double descent’
While all specimens have some Neanderthal features, some aspects of their shape are more typical of modern human teeth.
This suggests that these were traits that were common in their population.
Research leader Prof. Chris Stringer, of London’s Natural History Museum, said: “Given that modern humans in some parts of Europe overlap with Neanderthals in some parts of Europe after 45,000 years ago, the unusual features of these La Cotte individuals suggest that they could have had a double Neanderthal. Modern human ancestry. “
At the time these individuals lived, the climate in this part of the world was colder than it is now and the sea level was several dozen meters lower.
Co-author Dr. Matt Pope, of the Institute of Archeology at University College London (UCL), said the area would be “fantastic for hunting” because of its “dead-end valleys and blind gorges”.
“Caves of that scale and size are extremely rare in that landscape,” he said, adding, “It seems to be embedded in their routines, returning to that place for tens of thousands of years.”
In fact, there is a record of habitation at the La Cotte site dating back to 250,000 years ago.
Human teeth are thought to be about 48,000 years old, close to the presumed Neanderthal extinction date of 40,000 years ago.
So, instead of dying out in the traditional sense, were Neanderthal groups simply included in the emerging modern human populations?
“This must now become a scenario under serious consideration, among others, and it will emerge as we gain a greater understanding of the genetic mixing process,” said Dr. Pope on BBC News.
“But sure, that word ‘extinct’ is now starting to lose its meaning, where you can see multiple episodes of mixing and retaining a significant portion of Neanderthal DNA in people outside sub-Saharan Africa.”
Neanderthals contributed 2-3% to the genomes – the genetic instruction booklet for making a person – of people with ancestors from outside Africa.
“This idea of a hybrid population could be tested by recovering ancient DNA from the teeth, something that is now being investigated,” said Prof. Stringer.
The study is published in the Journal of Human Evolution.