Evrim Yazgin
Cosmos science journalist
DNA from a fossilised Neanderthal found in France reveals he was part of a community which was isolated from other Neanderthal for 50,000 years.
The findings are detailed in a paper published in Cell Genomics.
The individual has been dubbed “Thorin” after a character created by novelist J. R. R. Tolkien. He was discovered in 2015 in the Grotte Mandrin cave system in the Rhône Valley of southeastern France.
Thorin represents a previously undescribed lineage of Neanderthal that diverged about 100,000 years ago and remained genetically isolated for more than 50,000 years.
The individual was found in sediment dated to 40,000–45,000 years ago. But genetic analysis suggested Thorin’s genome more closely resembled Neanderthals from 100,000 years ago.
“We worked for 7 years to find out who was wrong – archaeologists or genomicists,” says co-first author Ludovic Slimak a researcher at the Paul Sabatier University in Toulouse, France.
Turns out both were correct.
Genetic data showed that Thorin lived in a very cold climate, showing that he was around toward the end of the Neanderthal’s existence about 45,000 years ago. While other Neanderthal populations developed genetically, Thorin’s community remained isolated.
Only a 10-day walk away was another Neanderthal community, yet the Thorin Neanderthal were secluded.
“This genome is a remnant of some of the earliest Neanderthal populations in Europe,” says senior author Martin Sikora of the University of Copenhagen, Denmark. “The lineage leading to Thorin would have separated from the lineage leading to the other late Neanderthals around 105,000 years ago.”
“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 2 populations present at that time,” says co-first author Tharsika Vimala of the University of Copenhagen.
Uncovering that Neanderthal groups were small and isolated may help explain their demise about 40,000 years ago.
“It’s always a good thing for a population to be in contact with other populations,” says Vimala. “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.”
Understanding Neanderthal population structure requires further genome sequencing.
“I would guess that if we had more genomes from other regions during this similar time period, we would probably find other deeply structured populations,” says Sikora.
