An international team of scientists has sequenced the nuclear genomes of two Neanderthals who lived in Europe around 120,000 years ago. They found that the individuals were more genetically similar to later Neanderthals from Europe than to a roughly contemporaneous individual from Siberia. The findings reveal a stable, 80,000-year ancestry for European Neanderthals and suggest that this group may have migrated east and replaced some Siberian Neanderthal populations.
Recent studies have shown that last Neanderthals all belonged to a single group, descended from a common ancestor who lived 97,000 years ago.
However, a 90,000-year-old Neanderthal from Denisova Cave in Siberia appears to be more closely related to those late Neanderthals than to the so-called Altai Neanderthal found in the same cave, but dated to 120,000 years ago.
This suggests that there had been an early Neanderthal migration into Siberia, followed by a later migration from Europe that replaced the earlier population.
To clarify how this happened, Dr. Stéphane Peyrégne from the Max Planck Institute for Evolutionary Anthropology and colleagues obtained nuclear DNA samples from European Neanderthals — one from Hohlenstein-Stadel Cave in Germany and the other from Scladina Cave in Belgium.
Using advanced techniques to account for microbial and present-day human DNA contamination, the researchers found that Scladina and Hohlenstein-Stadel individuals were members of a population in Western Europe that gave rise to all currently identified Neanderthals except the Altai Neanderthal.
This suggests that the population to which these Neanderthals belonged lived in Western Europe contemporaneously with the Altai population in Siberia and later migrated east to replace them.
“The result is truly extraordinary and a stark contrast to the turbulent history of replacements, large-scale admixtures and extinctions that is seen in modern human history,” said senior author Dr. Kay Prüfer, from the Max Planck Institute for Evolutionary Anthropology and the Max Planck Institute for the Science of Human History.
Surprisingly, the team also found highly divergent mitochondrial DNA in Hohlenstein-Stadel Neanderthal, indicating an even more complex history that warrants further investigation.
“Early European Neanderthals may have inherited DNA from a yet undescribed population,” the scientists said.
“This unknown population could represent an isolated Neanderthal population yet to be discovered, or may be from a potentially larger population in Africa related to modern humans,” Dr. Peyrégne said.
The results were published in the journal Science Advances.
Stéphane Peyrégne et al. 2019. Nuclear DNA from two early Neandertals reveals 80,000 years of genetic continuity in Europe. Science Advances 5 (6): eaaw5873; doi: 10.1126/sciadv.aaw5873