Are whites the descendants of the Neanderthals

Half of the Neanderthal genes survived

In the course of human history, modern man has left the African continent and spread to Asia and Europe. According to calculations, that was about 50,000 to 80,000 years ago. Presumably in the Middle East, Homo sapiens met the Neanderthals, who until then had developed parallel to modern humans in Africa. This encounter sometimes gives rise to common offspring. Thousands of years later, the closest relative of people living today suddenly disappears, why is still unclear today.

However, as a current genetic analysis in the specialist journal “Nature” shows, 38 to 48 percent of his genome still exists in people's DNA, and that is distributed across all. “Each one of course only carries a small part. About two percent of our genome can be traced back to the Neanderthals. But this part is different for everyone. To put it simply, we added up the differences, ”explains study director Laurits Skov, who is currently working at the Max Planck Institute for Evolutionary Anthropology in Leipzig.

27,500 Icelanders examined

For the study, the researchers analyzed the genetic makeup of around 27,500 Icelanders. At a good 84 percent, the majority of the Neanderthal genome comes from Altai and Vindija Neanderthals. For twelve percent, the origin is unclear. A good three percent can be traced back to the Denisova people, a distant sister group of the Neanderthals. This is surprising in so far as, according to current knowledge, Neanderthals lived mainly in the west and Denisovans in the east. “We still know little about the Denisova man. There are only a few bones found in Asia. So far, remnants of the Denisova DNA have only been found in people from East Asia, Papua New Guinea and the Australian Aborigines. That's why we thought for a long time that they had no influence on people in Europe. "

How their genome will end up in Europe or Iceland cannot be answered today. However, the bioinformatician Skov has two theories: Either Denisovans like Neanderthals were already living in the Middle East when modern humans first arrived there. "Or Homo Sapiens not only met Neanderthals in the Middle East, but also prehistoric humans who already had genes from both of them." This theory goes back to a study from 2018. As the bones of a girl in Siberia showed, her mother was Neanderthal and her father was Denisovan. “We won't know what happened until we find bone fragments in the Middle East. That has not happened yet. "

How DNA Remnants Affect Us

In the genetic and health data of Icelanders, you can not only read off which of our extinct relatives has left their genetic fingerprint. Rather, you can see what the primeval human genetic information does in the body.

We already know from previous studies that Neanderthal DNA has an influence on the immune system and that genes from Denisova people have contributed to people being able to live better in higher altitudes such as Tibet. In this study, the researchers are now identifying five crucial mutations that are caused by early human genes.

One gene change indicates a lower risk of prostate cancer, two variants concern the lower hemoglobin level, which makes it easier for the body to adapt at an altitude of 4,000 meters, and the last two gene changes make it difficult for blood to clot or tend to make you smaller.

Many mutations selected

Meanwhile, however, the influence of genes is minimal, emphasizes Skov. Most of the gene variants have been selected out over time.

“When you have a small population, like the Neanderthals, inbreeding often occurs and there are many bad mutations in the genome. The moment the Neanderthals meet the Homo Sapiens, who were a larger population, many bad genetic changes are removed. "

Where the genetic disadvantage would be particularly great, one can no longer find any genetic material from early humans today. According to the study, this affects a quarter of the entire genome, including the entire X chromosome, according to Skov's analysis.

Europeans, Asians, Americans

The results of the study do not only apply to people in Iceland. Comparisons with genetic analyzes show that probably all people from Europe, Asia and beyond carry a part of Neanderthals. "We also find the small proportion of Denisovans in the genetic information available from Europeans, people from South and East Asians, and from natives of North America, with whom we compared the results."

The current study by the bioinformatician and his colleagues also tells something about the Neanderthals themselves. As accurate comparisons of the DNA of modern humans today and Neanderthals show, male Neanderthals had children earlier than men today. Neanderthal mothers, on the other hand, were older. “The older people are when they have children, the more genetic changes they will pass on. Depending on the age, other variants are also inherited. From this you can see what differences there are here. "

How much younger or older Neanderthal mothers and fathers were, however, cannot be said. The analysis would "fit in with what we already know about the Neanderthals. Life was hard in the past, there was probably little food and it took time to have enough energy to bear children. But that's only." my interpretations. "

Ruth Hutsteiner, Ö1 Science

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