A remarkable discovery in a cave in the Rhône Valley of France has shed new light on the complex history of Neanderthal populations. Researchers have unearthed fossilized remains of a Neanderthal, nicknamed ‘Thorin,’ that belong to an ancient and previously undescribed genetic lineage. This lineage diverged from other Neanderthals around 100,000 years ago and remained isolated for over 50,000 years, up until the species went extinct.
The study, published in Cell Genomics, indicates that Thorin’s community was incredibly insular. Despite living just a ten-day walk from other Neanderthal populations, Thorin’s ancestors did not mix with their neighbors for millennia. This isolation might have contributed to their extinction, as limited genetic variation can reduce adaptability to changing environments and pathogens.
Archaeologists discovered Thorin’s remains in the Grotte Mandrin cave system in 2015. Initially, they believed Thorin lived around 40,000 to 45,000 years ago, classifying him as a ‘late Neanderthal.’ However, DNA analysis revealed that his genetic material closely resembled that of much older Neanderthals, suggesting a unique lineage.
To resolve the age discrepancy, scientists analyzed isotopes from Thorin’s bones and teeth to understand the climate he lived in. The results showed that Thorin lived during a very cold period, consistent with the Ice Age conditions experienced by late Neanderthals. This finding confirmed that Thorin was indeed a late Neanderthal, whose community remained isolated for 50,000 years.
The genomic analysis showed that Thorin’s closest genetic relative was another Neanderthal found in Gibraltar, Spain. This suggests that there was an unknown Mediterranean population of Neanderthals whose range extended from the western tip of Europe to the Rhône Valley in France. However, the incomplete genetic material from these populations makes it challenging to fully confirm this hypothesis.
This extreme isolation might offer clues to why Neanderthals eventually disappeared. Modern humans, known for their sociable nature, maintained cultural connections across vast areas, which likely enhanced their resilience and adaptability. In contrast, the insular lifestyle of Neanderthals limited their genetic variation and social interactions, potentially making them more vulnerable to environmental changes and diseases.
The research team, including experts from Southern Cross University, The University of Adelaide, Université Toulouse, CNRS, University of Copenhagen, and Syft Technologies Ltd., emphasizes the need for more Neanderthal genomes to fully understand their population structures and reasons for their extinction.
‘It’s always beneficial for populations to interact,’ said Tharsika Vimala, a population geneticist at the University of Copenhagen and co-author of the study. ‘Prolonged isolation restricts genetic variation and limits social evolution, making it challenging for the population to adapt to new threats.’
This groundbreaking research not only provides a deeper understanding of Neanderthal history but also highlights the importance of connectivity and genetic diversity for the survival of species.
The study was funded by various organizations, including the Service Regional de l’Archeologie Auvergne Rhone-Alpes, the French CNRS, the city of Malataverne, the Lundbeck Foundation, the Danish National Research Foundation, the European Research Council, and the Australian Research Council.