Prehistoric teeth discovered at a site in Jersey reveal signs of a cross between Neanderthals and our own species, scientists say.
British experts have again studied 13 teeth found between 1910 and 1911 in La Cotte de St. Brelade, in the southwest of the island.
For a long time, they were considered typical Neanderthal specimens, but the reassessment also revealed characteristic features of modern human teeth.
The teeth may represent some of the last known traces of Neanderthal.
As such, they may even provide clues as to what caused our close evolutionary cousins to disappear.
Neanderthals evolved about 400,000 years ago and inhabited a large area of Western Europe to Siberia.
They were typically shorter and stockier than modern humans, with a thick bony overhang over their eyes.
They finally disappeared about 40,000 years ago, as do anatomically modern humans (Homo sapiens), a species recently arrived from Africa, was establishing itself in Europe.
However, the two types of humans may have overlapped for at least 5,000 years.
The teeth were discovered on a small granite ledge at the cave site.
They were previously considered to belong to a single Neanderthal individual. However, the new research found that there were at least two adults.
The researchers used computed tomography (CT) of the teeth to study them at a level of detail that was not available to researchers in the past.
‘Double ancestry’
Although all specimens have some Neanderthal characteristics, some aspects of their shape are more typical of modern human teeth.
This suggests that these were prevalent characteristics in its population.
Research leader Prof Chris Stringer of the Natural History Museum in London said: “Given that modern humans overlapped Neanderthals in some parts of Europe after 45,000 years ago, the unusual characteristics of these individuals from La Cotte suggest that they could have had a double Neanderthal – modern human ancestry. “
At the time these individuals were alive, the climate in this part of the world was colder than today and the sea level was tens of meters lower.
The co-author, Dr. Matt Pope, of the Institute of Archeology at University College London (UCL), said the area would have been “fantastic for hunting” because of its “dead-end valleys and blind ravines”.
“Caves of this scale and size are extremely rare in that landscape,” he said, adding: “It seems to be embedded in their routines, going back to that place for tens of thousands of years.”
In fact, there is a record of occupation on the La Cotte site that dates back to 250,000 years ago.
Human teeth are believed to be about 48,000 years old, close to the Neanderthal’s supposed extinction date, 40,000 years ago.
So, instead of becoming extinct in the traditional sense, were Neanderthal groups simply absorbed by the arriving modern human populations?
“This now needs to be a scenario that is seriously considered, alongside others, and will emerge as we have more understanding of the process of genetic mixing,” Pope told BBC News.
“But certainly, the word ‘extinct’ now begins to lose its meaning where you can see several episodes of mixing and the retention of a significant proportion of Neanderthal DNA in humans beyond Sub-Saharan Africa.”
Neanderthals contributed 2 to 3% of the genomes – the booklet of genetic instructions for making a person – of people with ancestors from outside Africa.
“This idea of a hybrid population could be tested by recovering old DNA from the teeth, something that is now under investigation,” said Professor Stringer.
The study was published in the Journal of Human Evolution.