The 2010 discovery of early human and Neanderthal interbreeding was a scientific breakthrough. Recent studies have shown that this genetic legacy has played a significant role in modern people’s lives, influencing circadian rhythms, immune system function, and pain perception.
However, scientists had struggled to understand how intermingling between the two groups may have shaped Neanderthals. A new study published in Science uses new techniques to paint a clearer picture.
The analysis reveals that early humans and Neanderthals exchanged DNA at multiple points over the past 250,000 years. This finding sheds light on how Neanderthals disappeared and potentially rewrites the story of human migration out of Africa.
Researchers suggest that very early human history was complex, with modern humans interacting with Neanderthals and other archaic humans much more frequently than previously recognized.
The study found three waves of mating between humans and Neanderthals: one around 200,000-250,000 years ago, another 100,000 years ago, and the last around 50,000-60,000 years ago. The most recent episode is widely acknowledged and was first identified in 2010.
The researchers discovered that the percentage of Homo sapiens DNA in the Neanderthal genome may have been as high as 10% more than 200,000 years ago and decreased over time; on average, it was around 2-3%.
The study used machine learning techniques to decode and sequence genomes from three Neanderthals, dating from 50,000 to 80,000 years ago. The researchers then compared this data with the genomes of 2,000 present-day humans.
The findings suggest that human populations were larger than previously thought, which may have led to the absorption of Neanderthal genes into the human gene pool. This could be a major reason why Neanderthals disappeared 40,000 years ago.
Source: https://www.ctvnews.ca/sci-tech/dna-analysis-sheds-light-on-how-neanderthals-disappeared-1.6984269