Unveiling a Prehistoric Mystery
In 2015, archaeologist Ludovic Slimak made a groundbreaking discovery in France’s Rhône Valley: five Neanderthal teeth in a rock shelter. This remarkable find, nicknamed Thorin after a character from “The Hobbit,” marked the first intact Neanderthal remains discovered in France since 1979. However, the significance of this find remained under wraps for nearly a decade as Slimak and his team meticulously worked to piece together its implications.
A genetic conundrum
Slimak, a researcher at France’s National Centre for Scientific Research and Paul Sabatier University in Toulouse, faced a significant challenge. “We faced a major issue,” Slimak explained. “The genetics was sure the Neanderthal we called Thorin was 105,000 years old. But we knew by (the specimen’s) archaeological context that it was somewhere between 40,000 to 50,000 years old.” This discrepancy between genetic and archaeological evidence posed a complex puzzle.
Decoding Thorin’s DNA
Published in the journal Cell Genomics, the research revealed that Thorin belonged to a lineage of Neanderthals isolated from other groups for approximately 50,000 years. This genetic isolation explained why Thorin’s DNA appeared older than it actually was. Until now, experts believed the Neanderthal population at the time of extinction was genetically homogeneous. However, the study unveiled the existence of at least two distinct populations in Western Europe.
Implications for Neanderthal extinction
“The Thorin population spent 50,000 years without exchanging genes with other Neanderthal populations,” Slimak noted. This isolation suggested that Neanderthal communities were small and insular, factors that could have contributed to their extinction. “They were happy in their valley and did not need to move, while Homo sapiens all the time they want to explore,” Slimak said. The lack of genetic variation and social interaction likely hindered the Neanderthals’ ability to adapt to changing climates or diseases.
Chris Stringer, research lead in human evolution at London’s Natural History Museum, who was not involved in the study, emphasized the broader implications of the findings. He explained that while early Homo sapiens interbred with Neanderthals, no corresponding genetic evidence has been found in Neanderthal fossils, including Thorin’s remains. This imbalance, combined with economic competition from Homo sapiens, could have led to the Neanderthals’ demographic collapse.
Ongoing excavations
Excavations at Grotte Mandrin, the rock shelter near Malataverne, France, continue slowly. Slimak and his team have uncovered more of Thorin’s remains, including 31 teeth, part of the jaw, and five finger bones. The discovery of two extra lower molars, a trait sometimes indicative of an inbred population, adds another layer to the mystery.
Resolving the genetic puzzle
To resolve the genetic mystery, the team analyzed chemical isotopes in Thorin’s bones and teeth, inferring the climate he lived in based on the water he consumed. This analysis confirmed Thorin’s remains were indeed much younger than initially suggested by genetics. “We worked for seven years to find out who was wrong — archaeologists or genomicists,” Slimak said.
A site of surprises
Slimak, who has been excavating Grotte Mandrin for over three decades, has uncovered numerous exciting finds, making it the only known site to have hosted alternating groups of both Homo sapiens and Neanderthals. The site also boasts the earliest evidence of bow and arrow use outside Africa. “Grotte Mandrin keeps delivering surprises,” said Stringer.
This discovery not only sheds light on the intricate history of Neanderthals but also provides crucial insights into the factors that may have led to their extinction.