Homo Sapiens and Neanderthals lived in the same geographical area for more than 30,000 years as a result of the modern human migration from Africa. Their cohabitation meant that the two species reproduced. A recent study suggests that these reports were more frequent than previously thought.
About 50,000 years ago, modern humans left Africa for Europe and then Asia. Homo sapiens discovered Neanderthals, which were present in Europe for at least 200 000 years. Cohabitation therefore took place between the two species. Recent discoveries have found out that sexual intercourse between the two species did happen. This has been proven by the “small share of Neanderthal” present in our DNA (about 2%). Some believed that although sexual intercourse between the two species was a reality, it was a very rare occurance. However a recent study now suggests these two species reproduced most frequently than previously believed.
When two sexually compatible species live side by side for about 30,000 years the two species will inevitably have intimate encounters. However the main question is, to what extent ? This is what Fernando A. Villanea and Joshua G. Schraiber of Washington State University (USA) have been trying to answer. Based on a large body of data about the modern human genome, researchers compared Neanderthal DNA models in people of Asian and European descent.
Researchers then used an automatic learning algorithm to evaluate all the crossover events that may have caused the Neanderthal DNA models they discovered. With the results of this test researchers discovered that the two species had a more complex relationship than initially supposed. There would have been multiple interactions between the two groups, and probably many sexual relations between the two species, leading to crossed offspring.
“We think that a probable explanation of our results is that the gene flow between modern humans and Neanderthals was continuous, and in a region somewhat restricted geographically“, notes the researchers and authors of the report found in Nature Ecologie & Evolution .
A history full of crossbreeding
We should remember Neanderthals mated with other species than just Homo Sapiens. A few months ago, a fragment of a teenagers bone was found in a cave in Siberia which suggests that our former cousins also had intimate interactions with the Denisovians, and produced crossed offspring.
It would seem that miscegenation already seemed to be the norm several tens of thousands of years ago. Sexual intercourse was indeed possible whenever these groups interacted as there is evidence that Homo Sapiens and Denisovians also mated. Inevitably these interactions leaves traces which is why these two species are still present in our DNA today.