Recent studies have refined the timeline for interbreeding between Neanderthals and modern humans, establishing it began around 50,500 years ago and persisted for approximately 7,000 years.
One study, published in the journal Nature, presents the oldest known modern human genome sequenced from a small group of early Europeans who had recently mixed with Neanderthals. Another study in Science analyzed several contemporary human genomes alongside 58 ancient genomes from modern human remains discovered throughout Eurasia.
The findings indicate that both modern humans and Neanderthals coexisted in Eurasia for a duration of 6,000 to 7,000 years, leading to the exchange of genetic material. Present-day Eurasians carry between 1% and 2% of their genome from Neanderthal ancestry.
New estimates suggest that the average date for Neanderthal and Homo sapiens interbreeding is approximately 47,000 years ago, refining earlier estimates that ranged from 54,000 to 41,000 years ago. Furthermore, the initial migration of modern humans from Africa into Eurasia is now thought to have occurred around 43,500 years ago, which is more recent than previously believed.
Priya Moorjani, a senior author of the Science study, highlighted that the genetic differences between the two groups were minimal, allowing them to interbreed and produce fertile offspring. This suggests that Neanderthals and early modern humans were more genetically similar than previously understood.
The research provides a more nuanced understanding of human migration patterns and the complexities of Neanderthal and modern human interactions, indicating that the mixing of these populations was a continuous process rather than sporadic.
Additionally, the studies found that certain Neanderthal genes, particularly those associated with immune function, skin pigmentation, and metabolism, may have provided advantageous traits to early modern humans, aiding their survival in harsh environments.