Evidence of long-lost Neanderthal tribe discovered inside cave

While the Neanderthal bones originally appeared to be 100,000 years old, seven years of research revealed something entirely different.

Michael Dahlstrom
·Environment Editor
·3-min read
Close-up picture of Thorin's fossilised bones.
DNA was extracted from Thorin's fossilised bones. Source: Cell Genomics

Found deep inside a system of caves, fossilised bones from a Neanderthal head have been revealed to have come from a member of a small, isolated tribe. It’s thought this lost community diverged from other populations over 100,000 years ago and remained genetically isolated.

Neanderthals are a humanoid species that developed alongside and even bred with modern people. And it’s believed up to four per cent of the genomes of non-African modern humans contain Neanderthal DNA.

The bones from the isolated Neanderthal group were originally uncovered in 2015 inside France’s Grotte Mandrin, a cave system that later housed early Homo sapiens. But new DNA analysis published in the journal Cell Genomics on Monday (European time) has revealed his bones are from a genetically distinct group.

“Until now, the story has been that at the time of the extinction there was just one Neanderthal population that was genetically homogeneous, but now we know that there were at least two populations present at that time,” lead author Tharsika Vimala said.

The team examined DNA from the teeth and jaw from a Neanderthal man who researchers named Thorin, after a Lord of the Rings character. They compared his full genome sequence to those previously extracted from other Neanderthals.

Background: The cave system where Thorin was found. Inset: the exact location of his bones.
A map indicates where in the Grotte Mandrin the Neanderthal named Thorin was found in 2015. Source: Thilo Parg/Wikimedia Commons/Cell Genomics

Because his genetics closely resembled the remains of 100,000-year-old communities it was originally thought he was an early Neanderthal. But this result contradicted analysis of Thorin’s location within the cave’s sediment which suggested he lived 40,000 to 45,000 years ago.

“We worked for seven years to find out who was wrong—archeologists or genomicists,” the Université Toulouse’s Ludovic Slimak said.

To solve the mystery, the research team had to get extremely detailed. They analysed isotopes, a type of atom believed to be the smallest unit of matter that can retain all the chemical properties of an element. And this gave them a new understanding of the climate he lived in. They discovered he’d lived in cold weather which was consistent with the ice age conditions of the late Neanderthals.

A reconstruction of a Neanderthal face next to a skull.
Reconstructions of Neanderthals reveal how closely they resembled modern humans. Source: Getty

It's believed Thorin lived between 42,000 to 50,000 years ago. Because his genome closely resembles Neanderthal bones from Gibraltar, it's thought his tribe could have migrated from Gibraltar.

“This means there was an unknown Mediterranean population of Neanderthals whose population spanned from the most western tip of Europe all the way to the Rhône Valley in France,” Slimak said.

Because the population became isolated from other Neanderthals, it’s believed this could have played a role in it being eventually wiped out.

“When you are isolated for a long time, you limit the genetic variation that you have, which means you have less ability to adapt to changing climates and pathogens, and it also limits you socially because you're not sharing knowledge or evolving as a population,” Vimala, a population geneticist at the University of Copenhagen said.

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