A New DNA Revelation Rewrites The History of The Neanderthals in Europe

An international research collaboration has identified a severe Neanderthal population collapse beginning roughly 75,000 years ago.

Although numbers later recovered for a time, nearly all Late Neanderthals in Europe appear to have been descendants of one small group.

That limited genetic diversity may have played a part in their eventual extinction, thought to have occurred around 40,000 years ago.

"We have evidence that Neanderthals inhabited Europe continuously between 400,000 and 40,000 years ago," says paleogeneticist Cosimo Posth, from the University of Tübingen in Germany.

"However, we have only fragmentary details of their population history. So far, we know very little about the evolutionary developments that preceded their extinction."

Neanderthals, the Ice Age, and a refugium in south-western France

To explore what happened, the team behind the new study brought together DNA work and existing archaeological evidence. Their combined interpretation suggests that, about 75,000 years ago, Ice Age conditions may have pushed widely dispersed Neanderthal groups to withdraw into a single safe area-a refugium-somewhere in south-western France.

Late Neanderthals and mitochondrial DNA (mtDNA) across Europe

The Late Neanderthals examined in this research lived between 60,000 and 40,000 years ago. The scientists extracted and analysed mitochondrial DNA (mtDNA)-inherited through the maternal line-from bones and teeth belonging to 59 individual Neanderthals.

Although mtDNA does not provide a complete genome in the way nuclear DNA does, it tends to persist in the environment over tens of thousands of years. It can also be recovered more readily from ancient remains, as in this case.

Using statistical methods on the mtDNA data, the researchers identified 65,000 years ago as the point when the population’s genetics began to diversify markedly again-around the time Neanderthals may have been able to spread out beyond their Ice Age refugium.

Even though the mtDNA samples came from a broad geographic range, one maternal genetic branch was prevalent across the dataset, implying shared ancestry from an unexpectedly small number of individuals.

"This explains why almost all Late Neanderthals sequenced so far – from the Iberian Peninsula to the Caucasus – belong to the same line of inherited mitochondrial DNA," says Posth.

A renewed drop in genetic diversity before extinction

The pattern did not remain stable. The mtDNA results also indicated an abrupt, pronounced fall in Neanderthal genetic diversity between 45,000 and 42,000 years ago.

This points to a major and rapid reduction in population size prior to their final disappearance, which is believed to be around 40,000 years ago.

Overall, the findings strongly suggest a species that repeatedly expanded across the landscape and then fragmented into smaller groups-an arrangement that can heighten vulnerability to natural catastrophes, environmental stress, and the consequences of low genetic diversity (including disease and harmful mutations).

What the timeline implies about European Neanderthal ancestry

Although reconstructing the sequence of events requires several assumptions, and mtDNA cannot offer the full resolution that complete DNA records can, the argument assembled by the study is persuasive.

On this view, European Neanderthal ancestry is unlikely to have followed a simple, straight line. Instead, it appears to have narrowed, expanded once more, and then collapsed again before extinction-this is the storyline supported here.

Each additional Neanderthal study adds further detail to this remarkable chapter of history, shortly before Homo sapiens began to emerge as the planet’s most dominant species. Greater insight into Neanderthals often helps sharpen our understanding of our own species and our own past.

Combining mtDNA and archaeology to reconstruct Neanderthal demographic history

The work also highlights how applying multiple analytical approaches within the same study-here, mtDNA alongside a broader set of archaeological records charting Neanderthal movements through time-can help rebuild ancient history in a meaningful way.

"This allowed us to combine the two lines of evidence and reconstruct the demographic history of Neanderthals in terms of space and time," says Jesper Borre Pedersen, a paleolithic archaeologist from the University of Tübingen.

The research has been published in PNAS.