Do You Have a Low Pain Threshold? Blame Your Neanderthal Genes
Researchers believe that Neanderthals had a lower pain threshold than modern humans. A study has shown that because of genetic mutations our extinct relatives were more sensitive to pain. We typically think of Neanderthals as being strong and hardy, but now it appears that they were not as tough as we once thought. The findings are allowing researchers insight into archaic humans and enabling them to better understand the different pain thresholds of modern humans.
Evolutionary geneticists, from the Max Planck Institute for Evolutionary Anthropology in Germany and the Karolinska Institutet in Sweden, conducted a genome study of Neanderthals using remains found in caves in Russia and Croatia. It has been hard to identify mutations in archaic human genomes. According to Nature, these samples were very high-quality genomes and they allowed researchers to “confidently identify mutations that were probably common in Neanderthals, yet very rare in humans.” This research was only possible because of breakthrough technology.
Evolutionary geneticists conducted a genome study of Neanderthals using remains found in caves in Russia and Croatia. (gerasimov174 / Adobe Stock)
Pain and Genetic Mutations
Experts were able to identify a gene called SCN9A, which encodes a protein known as NaV1.7. NaV1.7 acts like a channel to carry pain signals. The study found that archaic humans had three mutations in this protein and that this was likely common in the wider population. The protein is important for sending messages, in the ion channel, transmitting pain to the brain and spine. Hugo Zeberg of the Karolinska Institutet in Stockholm, explained its function clearly in Nature: “People have described it as a volume knob, setting the gain of the pain in nerve fibres.” Some mutations result in people feeling chronic pain constantly, while others feel no pain at all.
Pain is conveyed via specialized nerve cells that are stimulated when the body feels discomfort or harmful sensations in some part of the body. The three mutations can turn “Nav1.7 into a trigger-happy channel capable of kicking off painful impulses far sooner than unmutated forms,” reports Science Alert. Pain involves a suite of genes and physiological process, but researchers are confident that the mutations they identified mean that Neanderthals were more sensitive to pain than the majority of modern humans. Svante Pääbo of the Max Planck Institute, who also took part in the study, told Science Daily that this work showed that the Neanderthal “threshold for initiating pain impulses was lower than in most present-day humans.”
The study examined the genomes of over 2,500 present-day humans to look for the three mutations. (Zeberg et. al / Current Biology)
The Evolution of Pain
It is likely that this was not a result of random mutation but that it was because of evolution. Science Alert states that “it's not hard to imagine that turning up that pain volume knob might have come in handy for our stocky hominin cousins, faced with dealing with trauma in some pretty brutal environments.” Having a lower sensitivity to pain could mean that they had to have stronger social networks to survive. Based on previous studies, Neanderthals who had been injured were nursed and there is even evidence of the use of natural painkillers. The results add to the evidence that archaic humans were very sophisticated. Part of this could be a result of their low pain threshold.
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This discovery has important implications for our understanding of how modern human experience pain. Neanderthals and modern humans have a common ancestor and at some point, between 300,000 and 80,000 years ago they diverged. The Neanderthals inhabited much of Eurasia and they frequently mated with Homo Sapiens. As a result, many people today carry their genes. It is believed that they became extinct, possibly because of competition from modern humans, but no-one is really sure.
Having a lower sensitivity to pain could mean that Neanderthals had to have stronger social networks to survive. (Gorodenkoff / Adobe Stock)
Modern Humans With Neanderthal Mutations Experience More Pain
The researchers conducted a study to find out if modern humans have the mutations in their genome. They examined a huge data base of people from the United Kingdom. “Modern British people who had inherited the Neanderthal mutations reported experiencing more pain in their lives,” reports Science. Their ion channel is more easily stimulated and as a result they receive more pain signals to the brain. Only those who have all three mutations of the protein are likely to be more sensitive to pain. Zeberg explained to Science Daily that “the full Neanderthal variant carrying three amino acid substitutions leads to heightened pain sensitivity in present-day people.”
“On a molecular level, the Neanderthal ion channel is more easily activated which may explain why people who inherited it have a lowered pain threshold,” continues Zeberg in Science Daily. This study demonstrates that the Neanderthals genetic inheritance of some people could explain unique physiological processes and even medical issues. Work on the genome sequencing of Neanderthals is continuing and will provide more fascinating insights into our extinct relatives.
Top image: Evolutionary geneticists conducting a genome study have found that Neanderthals had a lower pain threshold than the majority of modern humans. Source: proct_ab / Adobe Stock
By Ed Whelan