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Researchers Neanderthal genes reinforce our immune system
The Neanderthals has been extinct for about 30,000 years. But apparently we humans still carry traces of our former relatives in us, which have a positive effect on health. This was confirmed by two independent research projects from Leipzig and Paris. Accordingly, the Neanderthal genes strengthen our immune system and thus provide better protection against infections.
Extinct for 30,000 years
The so-called "Neanderthal" (scientifically: "Homo neanderthalensis") is an extinct relatives of today's human (Homo sapiens) for several decades. He developed in Europe at the same time as the Homo Sapiens in Africa, both had the same African ancestors with the Homo erectus. However, before the two human species spread across Europe and Asia, they apparently had intercourse with each other thousands of years ago - because researchers showed a few years ago that the people living on these continents today carry one to four percent of the Neanderthal genome.
Great progress in the study of human genes. Picture: anibal - fotolia Positive effects on the body's defense
But what significance do cross-species relationships have for human evolution? Leipzig researchers from the Max Planck Institute for Evolutionary Anthropology, scientists from the French research institute CNRS and the Paris Pasteur Institute devoted themselves to this question and came up with interesting results in two independent studies. Thus, the blends would bring health benefits to some of today's descendants, as Neanderthal genes have a positive effect on the immune system and increase protection against infectious diseases. At the same time, the inherited DNA components can also have a downside, because they may favor the emergence of allergies.
Immungene have different levels of Neanderthals
Some innate immunogens such as the so-called "toll-like receptors" (TLR) showed a higher proportion of Neanderthals than the rest of the genome, according to Lluis Quintana-Murci from the Pasteur Institute and CNRS in a statement from the Max Planck Society. "This shows how important the cross-species exchange of genes for the evolution of the innate immune system in humans could have been," explains the expert. The TLR genes therefore act on the cell surface, where they detect and combat components of bacteria, fungi and parasites.
In their study, the French scientists investigated the evolution of the innate immune system and analyzed both the genome data of living humans and the genome sequences of old hominins. It turned out that there had been little change in some immunizations over a long period of time. For other genes, on the other hand, a new variant was recognized, which quickly became established in order to obtain e.g. to adapt to changed environmental conditions. Thus, most adaptations to protein-coding genes would have occurred during the last 6,000 to 13,000 years, as humans progressively developed from hunter-gatherer agriculture.
Possible association with increased susceptibility to allergies
The Leipzig researchers came to the same conclusion, but they did not directly examine the immune system, but the functional importance of genes that modern man inherited from earlier species. They found the same three TLR genes as the French counterparts, with two of the gene variants resembling the Neanderthal genome, while the third more closely resembled the Denisova genome. These are also a population of the genus "Homo", which lived in southern Siberia some 40,000 years ago.
In addition, the team came to Dr. Janet Kelso and dr. Michael Dannemann from the Max Planck Institute for Evolutionary Anthropology in Leipzig concluded that these gene variants represent an advantage for the carrier in that the old variants increase the activity of the TLR genes and strengthen the body's defense. Thus, on the one hand, there is better protection against infections - but at the same time, susceptibility to allergies may also be increased, according to the Institute's statement.
Adaptations to the environment benefit modern humans
"Both studies show that intermingling with ancient human beings has a functional impact on modern humans, including better adaptation to our environment, such as providing us with more resistance to pathogens or facilitating the processing of new food resources," says Kelso. whose study was recently published in the American Journal of Human Genetics.
Although the scientist sounds "surprisingly", it is "plausible," because "as modern humans populated Europe and the western part of Asia, Neanderthals had already lived there for 200,000 years, absorbing their climate, food and pathogens Region well adapted "explains Kelso further. From these adaptations, the modern man could profit by mixing with the old human species.
According to Dr. Michael Dannemann carries a European two percent Neanderthal DNA in itself, the frequency in certain regions of the genome - such as the TLR defense genes - is significantly increased. "This is still reflected in man today. Whether it is still an advantage or a disadvantage or completely neutral today, we can not say, "Dr. Michael Dannemann told the news agency "dpa". (No)