In a groundbreaking new research, archaeologists discovered an ancient Neanderthal lineage that was effectively isolated for over 50,000 years which could explain the enigmatic cause of extinction. The site where the Neanderthal, named “Thorin” after the dwarf in The Hobbit, was found offers an unprecedented look at the social and genetic structure of some of our most distant relatives.
Uncovering Thorin’s Secrets
The nearly complete fossil itself was found in a cave complex in the Rhône Valley and belongs to an earlier, previously unknown lineage of Neanderthals that split off from most other Neanderthals at least 100,000 years ago. Genomic analysis suggests that he — dubbed Thorin by his French discoverers — lived as long 42,000–50,000 thousand years ago and was part of a small, fragmented community.
The finding, published in the journal Cell Genomics, suggests that late Neanderthals may not have been homogenous genetically, as scientists previously believed. The story so far has been that at the time of extinction, you had one genetically homogeneous Neanderthal population, but now we find that there were at least two populations present – the European and Siberian ones,’ says first author and University of Copenhagen population geneticist Tharsika Vimala.
If so, the results imply that some Neanderthal populations were more structured and diverse than they appear based on their previous history of isolation for tens of thousands of years. ‘The Thorins were people who disappeared 50,000 years ago without exchanging genes with the other Neanderthal populations,’ explains Ludovic Slimak, CNRS researcher at Université Toulouse Paul Sabatier and one of the first authors to have discovered Thorin We thus have 50 whole millennia when two Neanderthal populations, which lived about ten days’ walk away from each other, coexisted without even noticing one another. This is simply unimaginable for a Sapiens and reminds us of features that must have had the Neanderthals perceived our world biologically completely different from us Sapiens.’
The Enigma of Thorin’s Years
The site where the partially fossilized remains of Thorin were found near Trarza, Mauritania in West Africa GCSAS / UNSW Fossils from. 2015: an announcement that stunned researchers and pushed our understanding of human evolution back tens of thousands of years. The team’s archaeologists, who first found Thorin in his sediments entirely, initially put the date of living for the Neanderthal as some 40,000–45,000 years ago, shortly before his own species had gone extinct.
Yet the first genomic analysis indicated Thorin was far older than he should have been, on the basis of archaeological evidence alone; his genome was unlike any other late Neanderthal, and instead clustered with genomes from early Neanderthals who lived more than 100 millennia ago. Slimak notes, “We labored for 7 years to determine whether the archaeologists were accurate or whether it was we geneticists who erred.
The researchers also look at the isotopes in Thorin’s bones and his teeth to infer more about the climate that he was living through: Late Neanderthals were at home during the last cold phase of an ice age, whereas earlier Neanderthals would have known much warmer conditions. Isotopic analysis can reveal the climate in which an animal or human lived, and in the case of Thorin it shows he inhabited a very cold area, confirming that he is definitely a late Neanderthal. The finding illustrates the importance of a multidisciplinary approach in order to piece together the full picture of this complicated history.
Conclusion
The detection of Thorin, the archaic Neanderthal family unknown for more than 50,000 years provides a fresh look at the intricate social and genetic composition of these ancient hominins. Together, the results defy the dominant current model of genetically homogeneous Neanderthals and suggest instead that there were at least two biologically distinct groups living in relative isolation from one another.
It was what might have led to Neanderthals’ extinction, as isolation inbreeding is usually not very advantageous for a population’s fitness. To verify the findings, many more Neanderthal genomes will have to be sequenced from different places and times. The discovery of Thorin makes the whole field of ancestral research more fascinating (and complicated), and reiterates the need for a broad, multi-disciplinary approach to judge precisely who we used to be.
