Are Japanese and Koreans genetically different

Human evolution: did Neanderthals have sex with Asians more often?

Met on his journey around the world homo sapiens soon after the Neanderthals, after he left Africa - for example more than 50,000 years ago in Israel. From these encounters, children sometimes even emerged who, in turn, had fertile offspring themselves: This is why our genetic material today consists of around one to two percent of typical Neanderthal DNA sequences. The only exceptions here are people of exclusively African origin whose ancestors had no contact with the purely non-African Neanderthals. However, there are differences between Europeans and East Asians: Chinese, Japanese and Koreans have 20 percent more Neanderthal DNA than Germans or French. Joshua Akey and Benjamin Vernot from the University of Washington have now investigated why this is the case and published their study in the American Journal of Human Genetics.

So far, two hypotheses have been put forward for the regional differences. On the one hand, crossed Neanderthal genes could have harmed the health of modern humans and accordingly richly endowed direct descendants could have had fewer children of their own. As a result, the deleterious genes would gradually disappear from the population. With the Europeans, so the idea, this would have happened faster than with the East Asians, because the later East Asians who migrated to the east were a much smaller population. However, the smaller a reproductive group, the longer it takes for natural selection to eliminate harmful genes. Akey and Vernot have now ruled out this explanation by examining the so-called neutral regions of the European genome. Since these sections have no proven benefit, but also no disadvantage, they should disappear more slowly from the genome over time than harmful Neanderthal genetic material. But the two biologists found no evidence of this.

This article is contained in Spectrum - Die Woche, 8th week 2015

Instead, they support an alternative explanation. The early one Homo sapiens-Population in the Middle East split up after contact with Neanderthals. One part moved towards Europe, the other part towards Asia, where these people mingled with Neanderthals a second time - a second batch of corresponding DNA came into the Homo sapiens-Heritage. This also suggests a modeling by the two researchers that only sensibly resolved genetic differences between Europeans and East Asians when they had a second encounter with the Neanderthals. However, that would also mean that our relatives in East Asia died out later than previously thought. So far it is considered certain that Homo neanderthalensis finally disappeared about 30,000 to 40,000 years ago - and thus before the geographical separation of different groups of modern humans into Europeans and Asians. If the new theory is correct, Neanderthals would have to have survived longer in a previously unknown location to mix with the subgroup of modern humans who migrated eastwards.