Human evolution; Neanderthal pain gene (Introduction)

by David Turell , Friday, July 24, 2020, 18:52 (1371 days ago) @ David Turell

A 'probable' finding:

https://www.nature.com/articles/d41586-020-02202-x?utm_source=Nature+Briefing&utm_c...

"Despite their rough and tumble existence, Neanderthals had a biological predisposition to a heightened sense of pain, finds a first-of-its kind genome study published in Current Biology on 23 July1. Evolutionary geneticists found that the ancient human relatives carried three mutations in a gene encoding the protein NaV1.7, which conveys painful sensations to the spinal cord and brain. They also showed that in a sample of British people, those who had inherited the Neanderthal version of NaV1.7 tend to experience more pain than others.

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"Mutations in a gene called SCN9A — which encodes the NaV1.7 protein — stood out because all of the Neanderthals had three mutations that alter the shape of the protein. The mutated version of the gene was found on both sets of chromosomes in all three Neanderthals, hinting that it was common across their populations.

"NaV1.7 acts in the body’s nerves, where it is involved in controlling whether and to what extent painful signals are transmitted to the spinal cord and brain. “People have described it as a volume knob, setting the gain of the pain in nerve fibres,” says Zeberg. Some people with extremely rare genetic mutations that disable the protein do not feel pain2, whereas other changes can predispose people to chronic pain.

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"He and Pääbo then looked for humans with the Neanderthal version of NaV1.7. About 0.4% of participants in the UK Biobank, a genome database of half a million British people, who reported on their pain symptoms had one copy of the mutated gene. No one had two, like Neanderthals. Participants with the mutated version of the gene were about 7% more likely to report pain in their lives than were people without it.

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"Pääbo and Zeberg caution that their findings do not necessarily mean that Neanderthals would have felt more pain than modern humans. Sensations conveyed by NaV1.7 are processed and modified in the spinal cord and brain, which also contribute to the subjective experience of pain.

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"It is unclear whether the mutations evolved because they were beneficial. Neanderthal populations were small and had low genetic diversity — conditions that can help harmful mutations linger. But Pääbo says the change “smells” like a product of natural selection. He plans to sequence the genomes of around 100 Neanderthals, which could help provide answers.

"In any case, “pain is something adaptive”, points out Zeberg. “It’s not specifically bad to feel pain.'”

Comment: The study shows what we can learn by decoding DNA. I've always told patients pain is a friend as a helpful warning.