The only people on the planet whose ancestors did not interbreed with Neanderthals are the inhabitants of Sub-Saharan Africa. New research has shown that even the inhabitants of the northern part of the Black Continent have Neanderthal genes.
The decoding of the genome of our closest evolutionary relatives shows that the DNA of an average Eurasian is 1-4% of the genetic material of Neanderthals. Obviously, sex between representatives of the two species was rarely productive, but no matter how many offspring there were, it was enough to pass on to a reasonable person important genes that strengthened his immunity.
Since it has been established that people living now outside Africa have more in common with Neanderthals than Africans, it is logical to assume that interbreeding took place outside the Black Continent, when the first groups of Homo sapiens began to settle in the Middle East (no earlier than 100 thousand years back).
There is another, more complex point of view: Neanderthals and modern non-Africans had a common ancestor, which about 230 thousand years ago split from the ancestors of modern Africans. The second scenario is theoretically possible, but recent studies have repeatedly confirmed the first hypothesis. There was no sensation this time: an analysis of 780,000 genetic variants of 125 people, representing seven groups of North Africans, showed that there is much more Neanderthal DNA in these DNA than in Sub-Saharan Africans.
The level of Neanderthal genes in these populations is comparable to the Eurasian one. Scientists have also found that this Neanderthal genetic signal is higher in those North African populations whose ancestors had relatively little interbreeding with modern inhabitants of the Middle East and Europe. This suggests that the signal comes directly from ancient interbreeding with Neanderthals, and not from recent connections with other people whose ancestors were confused with a different species.
Thus, the only populations of modern humanity without a Neanderthal admixture are groups south of the Sahara. According to the researchers, the results obtained do not mean that the Neanderthals migrated to Africa and came into contact with the local population there.
An intimate situation developed more likely in the Middle East, from where some groups returned back to North Africa, assimilating or exterminating their ancestral populations. In addition, the study hints that the North African population was not a source of migration to the Middle East. Most likely, the inhabitants of East Africa became the pioneers. The results of the genetic analysis are published in the journal PLoS ONE.
