Tag Archives: Neanderthal

Reversal of Earth’s magnetic poles may have triggered Neanderthal extinction — and it could happen again

February 19, 2021 Admin Leave a comment

The Earth’s magnetic field protects us, acting as a shield against the solar wind (a stream of charged particles and radiation) that flows out from the sun. But the geomagnetic field is not stable in strength and direction, and it has the ability to flip or reverse itself.

Some 42,000 years ago, in an event known as the Laschamp Excursion, the poles did just that for around 800 years, before swapping back — but scientists were unsure exactly how or if it impacted the world.

Now, a team of researchers from Sydney’s University of New South Wales and the South Australian Museum say the flip, along with changing solar winds, could have triggered an array of dramatic climate shifts leading to environmental change and mass extinctions.

Scientists analyzed the rings found in ancient New Zealand kauri trees, some which had been preserved in sediments for more than 40,000 years, to create a timescale of how Earth’s atmosphere changed over time.

Using radiocarbon dating, the team studied cross sections of the trees — whose annual growth rings served as a natural time stamp — to track the changes in radiocarbon levels during the pole reversal.

“Using the ancient trees we could measure, and date, the spike in atmospheric radiocarbon levels caused by the collapse of Earth’s magnetic field,” Chris Turney, a professor at UNSW Science, director of the university’s Earth and Sustainability Science Research Center and co-lead author of the study, said in a statement.

The team compared their new timescale with site records from caves, ice cores and peat bogs around the world.

‘End of days’

Researchers found that the reversal led to “pronounced climate change.” Their modeling showed that ice sheet and glacier growth in North America and shifts in major wind belts and tropical storm systems could be traced back to the period of the magnetic pole switch, which scientists named the “Adams Event.”

“Effectively, the Earth’s magnetic field almost disappeared, and it opened the planet up to all these high energy particles from outer space. It would’ve been an incredibly scary time, almost like the end of days,” Turney said.

Researchers say the Adams Event could explain many of Earth’s evolutionary mysteries, including the extinction of Neanderthals and the sudden widespread appearance of figurative art in caves worldwide.

The phenomenon would have led to some dramatic and dazzling events. In the lead-up to the Adams Event, the Earth’s magnetic field dropped to only 0% to 6% of its strength, while the Sun experienced several long lasting periods of quiet solar activity.

“We essentially had no magnetic field at all — our cosmic radiation shield was totally gone,” Turney said.

The weakening of the magnetic field meant that more space weather, such as solar flares and galactic cosmic rays, could head to Earth.

“Unfiltered radiation from space ripped apart air particles in Earth’s atmosphere, separating electrons and emitting light — a process called ionisation,” said Turney in a statement. “The ionised air ‘fried’ the Ozone layer, triggering a ripple of climate change across the globe.”

During this time, Earth’s inhabitants would have been subjected to some dazzling displays — northern and southern lights, caused by solar winds hitting the Earth’s atmosphere, would have been frequent. Meanwhile, the ionized air would’ve increased the frequency of electrical storms — something that scientists think caused humans to seek shelter in caves.

“The common cave art motif of red ochre handprints may signal it was being used as sunscreen, a technique still used today by some groups,” Alan Cooper, honorary researcher at the South Australian Museum, said in a statement.

“The amazing images created in the caves during this time have been preserved, while other art out in open areas has since eroded, making it appear that art suddenly starts 42,000 years ago,” Cooper, co-lead author, added.

An upcoming reversal

In the paper, published in the journal Science, experts say there is currently rapid movement of the north magnetic pole across the Northern Hemisphere — which could signal another reversal is on the cards.

“This speed — alongside the weakening of Earth’s magnetic field by around nine per cent in the past 170 years — could indicate an upcoming reversal,” said Cooper.

“If a similar event happened today, the consequences would be huge for modern society. Incoming cosmic radiation would destroy our electric power grids and satellite networks,” he said.

Human activity has already pushed carbon in the atmosphere to levels “never seen by humanity before,” Cooper said.

“A magnetic pole reversal or extreme change in Sun activity would be unprecedented climate change accelerants. We urgently need to get carbon emissions down before such a random event happens again,” he added.

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Neanderthal genes could lower some people’s risk of severe COVID-19

February 18, 2021 Admin Leave a comment

Some people may have genes inherited from Neanderthals that reduce their risk of severe COVID-19 by 22%, a study found.
But the same researchers previously found that Neanderthal DNA can also put people at higher risk of respiratory failure due to COVID-19.
The inherited genes are more common in Europe and Asia.
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As an emergency room doctor, Hugo Zeberg has seen first-hand how widely COVID-19 infections can vary in severity. So he started digging for answers in a place that was familiar to him: the genome of Neanderthals.

Zeberg works at the Karolinska Institute in Sweden, and for the last couple of years, has been studying the degree to which Neanderthals — an extinct human species that died out about 40,000 years ago — passed along genes to modern humans through interbreeding.

Scientists think Neanderthal DNA makes up 1% to 2% of the genomes of many people of European and Asian descent. That small fraction of people’s genetic codes may hold important clues about our immune responses to pathogens.

In a study published this week, Zeberg and his colleague Svante Pääbo at the Max Planck Institute for Evolutionary Anthropology suggest that some people may have inherited a genetic advantage that reduces their risk of getting severe COVID-19 by 22%.

The advantage comes from a single haplotype — or long block of DNA — on chromosome 12. The same haplotype has been shown to protect people against West Nile, hepatitis C, and SARS (another coronavirus that shares many genetic similarities with the new one, SARS-CoV-2).

“The protective effect of this haplotype is probably not unique to SARS-CoV-2, but a more general part of our immune system,” Zeberg told Insider.

Some Neanderthal genes are helpful, others are harmful

An artistic representation of a Neanderthal male at the Neanderthal Museum in the Croatian town of Krapina.

Reuters

Zeberg and Pääbo found that the Neanderthal-inherited haplotype may have become more common among humans in the last 1,000 years. One possible explanation for this, Zeberg said, is the genes’ role in protecting people against other diseases caused by RNA viruses.

For their new study, the team relied on the genomes of three Neanderthals — two whose remains were found in southern Siberia and one from Croatia. The DNA dates back 50,000 to 120,000 years. They compared those Neanderthal genomes to the DNA of thousands of people with severe COVID-19.

The haplotype associated with less severe COVID-19 was found in all three Neanderthal genomes. It codes for proteins that activate enzymes that help degrade RNA viruses.

However, a prior study from Zeberg and Pääbo, published in September, showed that not all Neanderthal DNA confers an advantage. In that research, they found that some modern humans have inherited a haplotype on chromosome 3 that puts them at higher risk of respiratory failure due to COVID-19. That particular gene cluster was found in the Neanderthal from Croatia.

“If you have that variant, you have twice the risk of getting severely ill with COVID-19 — perhaps even more,” Zeberg said.

Zeberg’s research suggests that around 25% to 30% of people in Europe and Asia carry the protective haplotype, while up to 65% of people in South Asia and 16% of people in Europe carry the dangerous one. Unfortunately, he said, the protective haplotype doesn’t offset the risk of the dangerous one for those who have both.

Lingering mysteries about how genes influence COVID-19

A medical worker administers a COVID-19 test at a mobile testing unit in Marseille, France, on November 12, 2020.

For the most part, people in Africa don’t seem to have inherited any genes from Neanderthals.

“Neanderthals went to Europe and to Asia and lived there before modern humans,” Zeberg said. “Then modern humans came 100,000 years ago and they probably mixed 60,000 years ago. So Africa has never met Neanderthals.”

He added, though, that it’s possible that Africans inherited other genetic variants from different ancestors that confer their own protection against COVID-19 .

“There are variants in Africa that we and others are looking into,” Zeberg said.

Scientists test COVID-19 samples at New York City’s health department on April 23, 2020.

Scientists still don’t know how much of our protection against disease was inherited from ancient ancestors versus acquired more recently. Figuring that out is made more difficult by the fact that part of the Neanderthal genome is still missing.

But studying ancient genes could still help reveal more about how the body responds to the coronavirus. A December study, for instance, identified eight locations on human chromosomes where particular gene variants were more common among critically ill COVID-19 patients.

“If we can get a deeper understanding of how our evolutionary history has shaped our immune system, that can be valuable,” Zeberg said.

It’s possible, for example, that human ancestors relied on specific genes to protect them from viruses that have since died out. That may explain why certain people’s immune systems overreact to the new coronavirus, triggering inflammation that can prove fatal.

Zeberg said scientists have just started to scratch the surface of these findings.

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Did you survive Covid? Maybe you can thank your Neanderthal ancestors

February 17, 2021 Admin Leave a comment

Researchers found a genetic mutation that reduces the risk of severe Covid-19 infection by about 22%. It was found in all the samples they took of Neanderthal DNA, and in about 30% of samples from people of European and Asian origin.

The genetic region involved affects the body’s immune response to RNA viruses such as the coronavirus, as well as West Nile virus and hepatitis C virus, the researchers reported Tuesday in the Proceedings of the National Academy of Sciences.

“This region encodes proteins that activate enzymes that are important during infections with RNA viruses,” they wrote.

It may be one of those mutations that has been passed down over the millennia because it helped people survive, Svante Paabo and Hugo Zeberg of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany reported.

“We show that a haplotype on chromosome 12, which is associated with about a 22% reduction in relative risk of becoming severely ill with COVID-19 when infected by SARS-CoV-2, is inherited from Neandertals,” they wrote. “The relative risk of needing intensive care is reduced by about 22% per copy of the Neandertal haplotype,” they added.

“This haplotype is present at substantial frequencies in all regions of the world outside Africa,” they added. “It is present in populations in Eurasia and the Americas at carrier frequencies that often reach and exceed 50%.”

The finding could help explain why Black patients are so much more likely to suffer severe coronavirus disease. Neanderthals, who went extinct about 40,000 years ago, lived alongside and sometimes interbred with modern humans in Europe and Asia but not in Africa, and people of purely African descent do not carry Neanderthal DNA. Studies estimate that about 2% of DNA in people of European and Asian descent can be traced back to Neanderthals.

The team used samples taken from more than 2,200 living people with severe cases of coronavirus or matched controls. They found a genetic region that affected susceptibility to severe disease. Then they checked the DNA taken from the skeletons of four ancient humans — a 70,000-year-old Neanderthal from Siberia, a 50,000-year-old Neanderthal from Croatia, a 120,000-year-old Neanderthal from Denisova Cave in Siberia and an 80,000-year old sample from the same site from a Denisovan — another sub-species of ancient human. All four samples carried the same versions of that genetic sequence.

Last year, Paabo and Zeberg identified a genetic mutation inherited from Neanderthals that raised the risk of serious disease. As with most traits, susceptibility to disease and to serious outcomes is affected by a variety of genetic differences.

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What happens when you replace a human gene with its Neanderthal version?

February 11, 2021 Admin Leave a comment

Enlarge / The difference between modern human (left) and Neanderthal skulls means there must be some differences in how their brains develop.

What are the key differences between modern humans and our closest relatives, the Neanderthals and Denisovans? For the Neanderthals, there doesn’t look to be any sort of obvious difference. They used sophisticated tools, made art, and established themselves in some very harsh environments. But, as far as we can tell, their overall population was never particularly high. When modern humans arrived on the scene in Eurasia, our numbers grew larger, we spread even further, and the Neanderthals and Denisovans ended up displaced and eventually extinct.

With our ability to obtain ancient DNA, we’ve now gotten a look at the genomes of both Neanderthals and Denisovans, which allows us to ask a more specific question: could some of our differences be due to genetics?

The three species are close relatives, so the number of differences in our proteins are relatively small. But a large, international research team has identified one and engineered it back into stem cells obtained from modern humans. And the researchers found that neural tissue made of these cells has notable differences from the same tissue grown with the modern human version of this gene.

A not quite super NOVA

As the first step in their work, the researchers had to decide on a gene to target. As we mentioned above, the genomes of all three species are extremely similar. And the similarity only goes up when you look at those parts of the genome that encode proteins. An added complication is that some of the versions of genes found in Neanderthals are still found in a fraction of the modern human population. What the researchers wanted to do is find a gene where both Neanderthals and Denisovans had one version and nearly all modern humans had another.

Out of tens of thousands of genes, they found only 61 that passed this test. The one they chose to focus on was called NOVA1. Despite the explosive-sounding name, NOVA1 was simply named after having originally been found associated with cancer: Neuro-oncological ventral antigen 1. A look through the vertebrate family tree shows that Neanderthals and Denisovans share a version of NOVA1 with everything from other primates to chickens, meaning that it was present in the ancestor that mammals shared with dinosaurs.

Yet almost all humans have a different version of the gene (in a search of a quarter-million genomes in a database, the researchers were only able to identify three instances of the Neanderthal version). The difference is subtle—swapping in a closely related amino acid at a single location in the gene—but it is a difference. (For those who care, it’s isoleucine to valine.)

But NOVA1 is the sort of gene where small changes can potentially have a big impact. The RNAs that are used to make proteins are initially made of a mixture of useful parts separated by useless spacers that need to be spliced out. For some genes, the different parts can be spliced together in more than one way, allowing distinct forms of a protein to be made from the same starting RNA. NOVA1 regulates the splicing process and can determine which form of multiple genes gets made in cells where it’s active. For NOVA1, the cells where it’s active include many parts of the nervous system.

If that last paragraph was somewhat confusing, the short version is this: NOVA1 can change the types of proteins made in nerve cells. And, since behavior is one area where modern humans may have been different from Neanderthals, it’s an intriguing target of these sorts of studies.

On our nerves

Obviously, there are ethical issues with trying to see what the Neanderthal version would do in actual humans. But some technologies developed over the last decade or so now allow us to approach the question in a very different way. First, the researchers were able to take cells from two different people and convert them into stem cells, capable of developing into any cell in the body. Then, they used CRISPR gene-editing technology to convert the human version of the gene into the Neanderthal version. (Or, if you’re less charitable, you could call it the chicken version.)

After performing extensive checks that indicated that NOVA1 was the only gene altered by the editing, the researchers induced the stem cells to form the neurons typical of the brain’s cortex.

The clusters of neural cells that resulted were smaller when they were formed by cells with the Neanderthal version of NOVA1, although these clusters had a more complex surface shape. The cells with the Neanderthal version also grew more slowly and tended to undergo a process that ends in cell death more often. So it was clear that the Neanderthal version altered the stem cell’s behavior as they were converted into nerve cells.

Differences were apparent on the genetic level, as well. The research team looked for any genes that had altered activity (as measured by messenger RNA levels) in the cells with the Neanderthal NOVA1. There were quite a number of them, and they included some key regulators of neural development. And, as expected from a splicing regulator, there were hundreds of genes that saw changes to how their protein-coding RNAs were pieced together.

Many of these genes appear to be involved in the formation and activity of synapses, the individual connections among nerve cells that allow them to communicate with each other. Not surprisingly, this altered the behavior of those connections. Normally, nerve cells in culture form connections and coordinate their activity. In cells with the Neanderthal version of NOVA1, there was less coordination and a higher background of nerve cells firing off signals at random.

A matter of context

The results clearly show that having the Neanderthal version of NOVA1 is not a good thing for the nerve cells of modern humans. It will still take some more work, however, to determine whether all of the changes described here are the product of specific differences between the two forms of the protein or simply a consequence of the nerve cells being unhealthy due to the misregulation of genes.

But the researchers also caution against overinterpreting the results in general—while suggestive, these results are not a clear indication that gene changes make our brains fundamentally different from those of our closest relatives.

The evolution of the human version of this gene took place against a backdrop of many other subtle changes in human genes, either in their coding sequences or (more often) in the sequences that regulate their activity. Those changes could potentially offset any harmful effects caused by the differences in activity of the modern human version of NOVA1. Suddenly dropping in the original version of the gene again might only produce differences due to the mismatch between the gene and all of those compensations.

So, it’s going to take a while to sort out how much this one gene’s differences mean for human and Neanderthal brains. But the key thing is that it’s now possible to ask these questions at all. The technologies used to produce these results didn’t exist before this century—CRISPR gene editing is less than a decade old. So, the mere fact that we know this much is pretty astonishing.

Science, 2021. DOI: 10.1126/science.aax2537 (About DOIs).

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Researchers Just Looked at Neanderthal Poop to Understand Their Guts

February 5, 2021 Admin Leave a comment

The site at El Salt, Spain, where ancient poop keeps turning up.

Photo: University of Bologna

Around 50,000 years ago, a bunch of Neanderthals made a home—and a bathroom—out of what is now a rocky escarpment south of Valencia, Spain. Over the last few years, some of those paleo-poops, the oldest known to come from a human species, have been excavated and analyzed. Now, researchers have caught a glimpse of the ecosystems that existed in the guts of those early hominins, from a fecal deposit in the remnants of a fire pit on the site.

Over 200 bacterial microorganisms were extracted from the ancient poop by an interdisciplinary team of archaeologists, microbiologists, and anthropologists. The researchers found a striking amount of consistency between the microbial residents of the Neanderthal gut and the sort of microbes that populate the guts of modern humans. That consistency shows many minuscule denizens of our insides are actually longstanding residents, living in us for hundreds of thousands of years, and have coevolved with the hominins they inhabit. The research was published in the Nature journal Communications Biology.

According to Marco Candela, a microbiologist at the University of Bologna and co-author of the paper, the team wanted “to see which microbiomes are coevolving with the Homo lineage in evolutionary time.” To do this, they looked for microbes that contemporary humans might share with Neanderthals.

Having an early reconstruction of a human gut is useful in contextualizing what our microbiomes look like today; researchers want to know which bacteria have remained with us and which have disappeared entirely from our internal ecosystems. Microorganisms with substantial staying power in the guts of mammals were termed “old friends” in the mid-2000s, and their co-evolution with us has been linked to the ways humans have lived for hundreds of thousands of years.

Understanding Neanderthals allows us to better chart our own evolutionary path.

Photo: CESAR MANSO/AFP via Getty Images (Getty Images)

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The oldest gut microbiome data for humans is about 8,000 years old—it doesn’t even precede the last ice age, which ended about 11,000 years ago. That has left researchers in the lurch when it comes to understanding the insides of our early ancestors. The Neanderthal poop pushes the chronology back some 40,000 years—shortly before Neanderthals as we know them disappear from the evolutionary record.

“The point is that we identified some microorganisms that are shared between modern humans and Neanderthals,” Candela said. “This means that these microorganisms populate the gut of the human lineage before the segregation of the Neanderthal and sapiens lineages.”

An important find in the Neanderthal poop was the inclusion of short-chain fatty acid-producing bacteria, many of which allow humans to eke out extra energy from dietary fiber, and one of which the researchers suggest may have provided health benefits to ancient mothers and their children. But just as good microbes hitchhiked through time in our guts, so too did the hell-raisers—the researchers also found bacterial pathogens in the feces that remain around today, causing oral and dental diseases in modern humans.

According to Candela, the microbiomes of populations that live in traditional, rural ways, like the Hazda, a group of hunter-gatherers in northern Tanzania, tend to have guts that are more alike. On the other side are humans who inhabit urban environments, which isolate our guts and make our bacterial residents less similar from person to person. The paper describes a wholesale loss in bacterial diversity in the modern human gut and a situation in which each of our guts aren’t talking to one another like they did in our evolutionary past. “Each of us is like an island,” Candela said.

Often, the human evolutionary path is framed heroically—out of many early humans, ours was the one to succeed. But as the Neanderthal microbiome shows, we were hardly alone for that journey. Plenty of micro-organisms had the same path.

“Based on these results, we can anticipate the symbiotic time-depth between humans and some co-resident microbes to be at least one million years,” wrote co-author Stephanie Schnorr in a Nature blog on the research. “This implies a fixed physiological relationship that is linked to normal development and health in longevity across both humans and Neanderthals as an ancient legacy.”

Hopefully, more feces will be studied in the future, so we can further unpack the guts that have made us who we are. For now, we can be grateful that the findings aren’t crap.

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Stone Age teeth hint at Neanderthal interbreeding

February 1, 2021 Admin Leave a comment

During this time, Homo sapiens and Neanderthals encountered each other and sometimes had sex and gave birth to children. The evidence is buried within our genes, DNA analysis has shown, with most Europeans having around 2% Neanderthal DNA in their genomes from this ancient interbreeding.

However, there has been relatively little direct physical evidence of these encounters and fossilized bones. Skeletons that have been found haven’t offered 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 could have belonged to individuals that had mixed Homo neanderthalensis and Homo sapiens ancestry.

The teeth, identified as being 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 shown that the choppers actually came from two different individuals who lived there 48,000 years ago. Seven of the teeth had both modern human and Neanderthal traits.

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

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

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

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

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

It “might be that this (is) a highly unusual population that developed this combination of traits in isolation – however at this time, because of the lower sea levels of the last Ice Age, Jersey was definitely connected to neighboring France, so isolation is unlikely,” he explained via email.

It was surprising to find this evidence of “hybrid” individuals with Neanderthal and Homo sapiens ancestry in Northwestern Europe, he said, because the earliest evidence of early modern human influence in Europe has been found much further east. Evidence in current-day Bulgaria dates back potentially 47,000 years ago, and in Iberia and and southern France before 42,000 years ago.

Similarly, what fossil evidence exists of interbreeding has also been found further east.

The most definitive case is from Oase Cave in Romania, where a 40,000-year-old jawbone was unearthed, with unusual features. Genetic analysis found that it had 9% Neanderthal DNA, from interbreeding that probably happened within the previous five generations, Stringer said.

A 50,000 year-old bone fragment discovered in 2018 within a Russian cave represented the first-known remains of a child with a Neanderthal mother and a father who was a Denisovan — another extinct relative of modern humans who is thought to have lived predominantly in Asia.

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

The La Cotte site in Jersey shows that Neanderthals used the cave for as much as 200,000 years, the Natural History Museum said, with the layers of earth showing repeated reoccupation by different Neanderthal groups and at least two heaps of mammoth bones.

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Ancient Jersey teeth find hints at Neanderthal mixing

February 1, 2021 Admin Leave a comment

The Neanderthal specimens have some features that are more characteristic of modern human teeth

Prehistoric teeth unearthed at a site in Jersey reveal signs of interbreeding between Neanderthals and our own species, scientists say.

UK experts re-studied 13 teeth found between 1910 and 1911 at La Cotte de St Brelade in the island’s south-west.

They were long regarded as being typical Neanderthal specimens, but the reassessment also uncovered features characteristic of modern human teeth.

The teeth may represent some of the last known Neanderthal remains.

As such, they might even yield clues to what caused the disappearance of our close evolutionary cousins.

The Neanderthals evolved around 400,000 years ago and inhabited a large area from western Europe to Siberia.

They were typically shorter and stockier than modern humans, with a thick ridge of bone overhanging the eyes.

They finally disappeared around 40,000 years ago, just as anatomically modern humans (Homo sapiens), a newly arrived species from Africa, was settling in Europe.

However, the two types of human 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 thought to belong to a single Neanderthal individual. However, the new research found they were from at least two adults.

The researchers used computed tomography (CT) scans of the teeth to study them at a level of detail that wasn’t available to researchers in the past.

‘Dual ancestry’

While all the specimens have some Neanderthal characteristics, some aspects of their shape are more typical of teeth from modern humans.

This suggests these were traits that were prevalent in their population.

Research leader Prof Chris Stringer, from London’s Natural History Museum, said: “Given that modern humans overlapped 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 dual Neanderthal-modern human ancestry.”

At the time these individuals were alive, the climate in this part of the world was colder than it is today and the sea level was tens of metres lower.

Co-author Dr Matt Pope, from the Institute of Archaeology at University College London (UCL), said the area would have been “fantastic for hunting”, because of its “dead-end valleys and blind gulleys”.

“Caves of that scale and size are extremely rare in that landscape,” he said, adding: “It seems to be embedded in their routines, coming back to that place for tens of thousands of years.”

The specimens were originally excavated more than 100 years ago

In fact, there is a record of occupation at the La Cotte site going back to 250,000 years ago.

The human teeth are thought to be around 48,000 years old, close to the presumed Neanderthal extinction date of 40,000 years ago.

So, rather than going extinct in the traditional sense, were Neanderthal groups simply absorbed into incoming modern human populations?

“This now needs to be a scenario that’s seriously considered, alongside others, and it’s going to emerge as we get more understanding of the process of genetic admixture,” Dr Pope told BBC News.

“But certainly, that word ‘extinct’ now starts to lose its meaning where you can see multiple episodes of admixture and the retention of a significant proportion of Neanderthal DNA in humans beyond sub-Saharan Africa.”

Neanderthals contributed 2-3% of the genomes – the genetic instruction booklet for making a person – of people with ancestry from outside Africa.

“This idea of a hybrid population could be tested by the recovery of ancient DNA from the teeth, something that is now under investigation,” said Prof Stringer.

The study has been published in the Journal of Human Evolution.