A new study has revealed that the last Neanderthals living in Western Europe were far more connected and genetically diverse than scientists once believed.
The findings challenge earlier ideas that these ancient humans were isolated, inbred populations that slowly disappeared because of poor genetic health.
The research, published in the journal Nature, examined DNA from 27 Neanderthal individuals who lived in what is now Belgium and France.
By comparing their genetic information, scientists were able to build the most detailed picture yet of Neanderthal populations during the final period before they became extinct around 40,000 years ago.
Neanderthals were close relatives of modern humans. They lived across Europe and parts of Asia for hundreds of thousands of years before disappearing. Scientists have long debated why they became extinct. Possible explanations include climate change, competition with modern humans, disease, and shrinking populations.
One popular idea suggested that the final Neanderthal groups were small, isolated and suffered from a lack of genetic diversity, making it harder for them to survive.
However, the new study paints a different picture.
The researchers found that the last Neanderthals were not isolated communities cut off from one another. Instead, they formed a network of connected groups that continued to exchange genes over long distances. This helped maintain greater genetic diversity than previously expected.
The study also found no evidence that these Neanderthal populations had recently mixed with modern humans before they disappeared. Although scientists know that Neanderthals and modern humans interbred at various times in history, this research suggests that such contact did not play a significant role in the final Neanderthal populations studied in Western Europe.
An important part of the research came from a Neanderthal fossil discovered at Les Cottés in France. The fossil had already attracted attention because earlier studies showed its DNA was linked to Neanderthal groups living much farther away than expected.
In the new research, this individual served as an important reference point for comparing newly analyzed Neanderthal genomes from France and Belgium. Together, the DNA evidence showed that the last Neanderthals carried genetic traces from several different ancestral groups.
Professor Marie Soressi from Leiden University, who helped lead the excavation of the Les Cottés fossil, said every newly sequenced Neanderthal genome provides valuable new information about how these ancient people lived.
She explained that researchers are only beginning to understand how complex Neanderthal societies may have been. Rather than studying single individuals, scientists can now start rebuilding entire communities, including their family relationships and the social networks that connected different groups across Europe.
The findings suggest that genetic decline alone was probably not the main reason Neanderthals disappeared. Instead, their extinction was likely caused by a combination of environmental changes and other challenges that scientists are still working to understand.
As more Neanderthal DNA becomes available from archaeological sites across Europe and Asia, researchers hope to uncover an even clearer picture of how these ancient humans lived, moved across the landscape and interacted with one another during the final chapters of their history.
