Credit: UCL
Key points:
- People who carry three gene variants inherited from Neanderthals are more sensitive to certain types of pain.
- The Neanderthal variants sensitize sensory neurons by altering the threshold at which a nerve impulse is generated.
- Past interbreeding with Neanderthals has influenced modern human genetics, especially in populations with high proportions of Native American ancestry.
A recent study, published in Communications Biology, finds that people who carry three gene variants inherited from Neanderthals are more sensitive to certain types of pain. These results indicate that past interbreeding with Neanderthals has influenced modern human genetics.
People possessing three Neanderthal variants in the SCN9A gene—M932L, V991L, and D1908G—have greater pain sensitivity. The SCN9A gene encodes a sodium channel that is highly expressed in sensory neurons receiving signals from damaged tissues.
Researchers analyzed the genetic data from 5,971 people from Brazil, Chile, Colombia, Mexico, and Peru to examine the region containing the SCN9A gene. The D1908G variant of the gene was present in approximately 20% of chromosomes in the population, while about 30% of chromosomes with the variant also carried the M932L and V991L variants. The Neanderthal variants were more common in populations with higher proportions of Native American ancestry likely due to random chance and population bottlenecks that occurred during the initial occupation of the Americas.
Additionally, the research team measured the pain thresholds of 1,963 people from Colombia following exposure to a range of stimuli. The three SCN9A variants were associated with a lower pain threshold in response to skin pricking after prior exposure to mustard oil, but not in response to heat or pressure. Carrying all three variants was linked to greater pain sensitivity than possessing just one.
Researchers believe that the Neanderthal SNC9A variants sensitize sensory neurons by altering the threshold for generating a nerve impulse. While acute pain can modulate behavior and prevent further injury, more research is needed to explore the evolutionary role of these variants.
“Pain sensitivity is an important survival trait that enables us to avoid painful things that could cause us serious harm,” said Kaustubh Adhikari, professor at University College London. “Our findings suggest that Neanderthals may have been more sensitive to certain types of pain, but further research is needed for us to understand why that is the case, and whether these specific variants were evolutionarily advantageous.”