Are you sensitive to pain? Blame your heredity neandertal

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There is a myth that neanderthals they lived lives especially violent and dangerous, marked by hunting mammoths, bison and other wild animals. This idea is based on the numerous fractures, deformations and holes found in their fossils, especially in the head and neck. His days, with stones or points of flint as the only weapon against the wild nature, they were hard without a doubt, although some researchers do not believe that they were significantly more than those of the first individuals of our species, Homo sapiens.

This existence was harsh and austere in the Paleolithic might lead one to think that the neanderthals were a few types strong and agerridos, that can go out there with open wounds without a murmur, but were perhaps more sensitive than believed. According to a new research conducted by Svante Pääbo, of the Max Planck Institute for Evolutionary Anthropology in Leipzig, and his colleague, Hugo Zeberg, the Karolinska Institute of Stockholm, this human species that became extinct some 40,000 years ago, had a predisposition biological to feel more pain.

the study of The genome, published in “Current Biology”, points out that these ancient relatives to humans carrying three mutations in a gene that encodes a protein Na V 1.7, which transmits painful sensations to the spinal cord and the brain. The report also showed that in a sample of british, those who had inherited the version neanderthal of Na V 1.7 are likely to experience more pain than others.

Genomes of quality

As explained on the website of “Nature”, Pääbo and his team were able to identify mutations, probably common in neanderthals, thanks to the generation of three genomes of neanderthal of the high quality of DNA found in caves in Croatia and Russia. Mutations in a gene called SCN9A, which encodes the protein Na V 1.7, is highlighted because all the neanderthals had three that alter the shape of the protein. The mutated version of the gene was found in both sets of chromosomes in the three neanderthals, suggesting that it was common in all the populations.

Na V 1.7 acts on the nerves of the body, where it is involved in the control of if painful signals are transmitted to the spinal cord and brain, and to what extent. Some people with genetic mutations that are extremely rare that disable the protein does not feel pain, while other changes may predispose people to chronic pain.

To investigate how the mutations may have altered the nerves of the neanderthals, Zeberg expressed his version of Na V 1.7 in frog eggs and kidney cells of a human. The protein was more active in cells with three mutations in the cells without the changes. In nerve fibers, this would reduce the threshold to transmit a signal painful.

The researchers searched for people with the version neanderthal of Na V 1.7. Around 0.4% of participants in the Uk Biobank, a database of the genome of half a million british, who reported on their pain symptoms had a copy of the mutated gene. No one had two, like the neanderthals. Participants with the mutated version of the gene had approximately 7% more likely to feel pain than people without it.

what about beneficial Mutations?

Pääbo and Zeberg warn that their findings do not necessarily mean that neanderthals would have felt more pain than modern humans. The sensations transmitted by Na V 1.7 is processed and modified in the spinal cord and the brain, which also contributes to the subjective experience of pain.

But why had these mutations? Do you feel more pain may be useful? It is not clear whether the mutations evolved because they were beneficial. Populations of neanderthals were small and had little genetic diversity, conditions that may help the persistence of harmful mutations. In any case, as pointed out by Zeberg, “is not specifically wrong to feel pain”.