Neanderthal DNA may shape how sensitive you are to pain, genetic analysis shows

A fluorescent blue DNA double helix structure Human cell biology DNA strands molecular structure in 3D illustration.
Three versions of a gene called SCN9A are thought to come from Neanderthals and seem to affect pain-detecting nerve cells in the body. (Image credit: jes2ufoto via Getty Images)

Neanderthal gene variants may boost the pain sensitivity of people who carry them and may be most common in populations with prevalent Native American ancestry, a new study finds.

The research, published Tuesday (Oct. 10) in the journal Communications Biology, focused on three versions of the SCN9A gene, which codes for a protein that shuttles sodium into cells and helps pain-detecting nerves send signals. People with any of the three variants are more sensitive to pain caused by being prodded with a sharp object, but not pain caused by heat or pressure. 

"In 2020, another group of researchers studied people of European ancestry and linked these Neanderthal gene variants to increased pain sensitivity," first study author Pierre Faux, a geneticist at the French National institute for Agriculture, Food and Environment, told Live Science.

"We extend these findings by studying Latin Americans and showing that these Neanderthal genetic variants are much more common in people with Native American ancestry," Faux said. "We also show the type of pain these variants affect, which wasn't known before."

Related: Mysterious 'Viking disease' linked to Neanderthal DNA

"We know that modern humans and Neanderthals interbred something like 50,000 to 70,000 years ago, and that modern humans first crossed over from Eurasia into the Americas by 15- to 20,000 years ago," Faux said.

"The high frequency of the Neanderthal variants in people with Native American ancestry could potentially be explained by a scenario where the Neanderthals carrying these variants happened to breed with the modern humans who eventually migrated into the Americas," he said.

"When we tested the participants' pain threshold by applying pressure, heat or cold, the gene variants did not affect pain sensitivity, so the Neanderthal variants only affected their response to pinprick pressure," Faux noted.

It is possible that carrying these gene variants gave Neanderthals, and the modern humans who first settled the Americas, some sort of survival benefit, Faux said. But that survival benefit wasn't necessarily related to pain sensitivity, he added.

"The modern humans who first reached North America would have had to bear harsh and cold conditions, so it could be that these variants have other effects beyond pain — for example, they could have somehow helped humans to cope with the cold," he said. In other words, the heightened sensitivity to sharp objects might have been just a side effect of another evolutionary change.

However, the evolutionary pressures that acted on SCN9A were likely complex, and "why Neanderthals might have had a greater pain sensitivity and whether introgression in SCN9A represented an advantage during human evolution remains to be determined," the authors wrote..

Nevertheless, it is interesting to know these gene variants, which have previously been linked to small fiber neuropathy — a painful nerve condition — would have also caused pain in our Neanderthal ancestors, Sulayman Dib-Hajj, a professor of Neurology at the Yale School of Medicine who was not involved in the study, told Live Science in an email.

Carissa Wong
Live Science Contributor

Carissa Wong is a freelance reporter who holds a PhD in cancer immunology from Cardiff University, in collaboration with the University of Bristol. She was formerly a staff writer at New Scientist magazine covering health, environment, technology, nature and ancient life, and has also written for MailOnline.