One newly described group of Neanderthals appeared to have never met their neighbors.
Scientists found a new lineage of the early humans that emerged about 100,000 years ago. They remained genetically stable for about 50,000 years ago and possessed genomes that differed from Neanderthals found elsewhere on Earth at that time, according to a report in the journal Cell Genomics.
Remarkably, the newly described Neanderthals lived within walking distance of the greater population. The findings have the potential to rewrite what we know about Neanderthals.
“Until now, the story has been that at the time of the extinction there was just one Neanderthal population that was genetically homogeneous,” first author and population geneticist Tharsika Vimala of the University of Copenhagen, said in a statement. “But now we know that there were at least two populations present at that time.”
New Discovery Reveals a Hidden Neanderthal Lineage
When Ludovic Slimak, National Centre for Scientific Research (CNRS) researcher of Université Toulouse Paul Sabatier, first found the fossils in 2015, he didn’t realize their full significance. The archeologist found the bones in Grotte Mandrin, a cave system in France. Scientists have found Homo sapien fossils there and are still excavating the site.
“This is the kind of unique discovery that an archaeologist can only dream of finding in a well-lived life,” says Ludovic Slimak, CNRS researcher of Université Toulouse Paul Sabatier. “A new population, unknown, that reshuffles the deck regarding the very structure of human populations at the time of the greatest extinction of humanity.”
The genomic revelation makes the finding especially significant — and came about almost as an afterthought. The team of archeologists initially thought that the fossil, which they named Thorin, based on the Tolkien character, was a late Neanderthal, based on the bones’ location within the sediment.
To pinpoint his age, the team took DNA from Thorin’s teeth and jaw, then compared it to previously sequenced Neanderthal genomes.
Read More: The Fascinating World of Neanderthal Diet, Language and Other Behaviors
Genetic Differences Could Explain Neanderthal Extinction
That’s when the scientists knew they were on to something special. They found that Thorin’s DNA more closely resembled Neanderthals that had lived over 100,000 years ago. Basically, his archeological age and genomic age didn’t seem to match up.
The team’s explanation is that the Grotte Mandrin residents pretty much stayed near their cavern home for about 50,000 years and didn’t intermingle with other Neanderthal communities.
The idea that Thorin’s community lived about a 10-day hike from the nearest known Neanderthal community prompted Slimak to re-assess what he thought he knew about how Neanderthals lived, which he wrote about in The Naked Neanderthal.
If Neanderthal communities were small and insular, like Thorin’s, that would help explain their eventual disappearance. Isolation could lead to lack of genetic diversity, which, in turn would make them more susceptible to changing climates and new diseases.
“This is probably the key that we were missing to understand this extinction of humanity,” says Slimak.
Read More: The Neanderthal Timeline Shows They Thrived for 400,000 Years, Then Disappeared
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Before joining Discover Magazine, Paul spent over 20 years as a science journalist, specializing in U.S. life science policy and global scientific career issues. He began his career in newspapers, but switched to scientific magazines. His work has appeared in publications including Science News, Science, Nature, and Scientific American.
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