The relationship between modern humans and Neanderthals is a fascinating topic that continues to be explored by researchers. While it is well-known that modern humans picked up some Neanderthal DNA through interbreeding as they expanded out of Africa, a recent study has shed new light on this interaction.
Published on Thursday, the study suggests that an early population of modern humans also left Africa and interbred with Neanderthals, introducing modern human DNA into the Neanderthal population. This finding challenges previous estimates of Neanderthal genetic diversity, indicating that their population may have been even smaller than previously thought.
One key piece of evidence supporting this theory is the genome of a Neanderthal from the Altai region of Siberia, dating back roughly 120,000 years. Despite predating the major out-of-Africa expansion of modern humans, this genome contains regions that match the human genome but are not present in the Denisovan lineage.
Researchers have proposed two main explanations for this genetic overlap. One possibility is that an ancestral population of modern humans left Africa around 200,000 years ago, leaving traces of their DNA in Siberian Neanderthals. Alternatively, it is suggested that some modern humans who picked up Neanderthal DNA during the out-of-Africa migration later returned to Africa, bringing Neanderthal DNA with them.
To investigate these hypotheses, a research team from Princeton University analyzed Neanderthal DNA in African populations using a large dataset of human genomes. The researchers hypothesized that the addition of modern human DNA to the Neanderthal population would have increased its genetic diversity. Therefore, if Neanderthal DNA found in African populations contains diverse regions of the Neanderthal genome, it would support this idea.
By studying the genetic diversity of Neanderthal DNA in African populations, researchers hope to gain a better understanding of the complex interactions between modern humans and Neanderthals. This study opens up new avenues for research into our shared genetic history and provides valuable insights into the origins of human diversity.
