Modern humans and Neanderthals interbred for thousands of years, resulting in positive effects on the pain sensitivity of their offspring. Pain is transmitted through human nerve cells, which are activated when a harmful influence affects a part of the body. Nerve cells are equipped with an ion channel, which is a crucial key in triggering a pain impulse that is transmitted through the nerve cells to the brain. Researchers from the Max Planck Institute in Leipzig and the Karolinska Institute in Sweden have published a study in the journal Current Biology, which shows that modern humans feel less pain than the Neanderthal variant, which has an ion channel. The increasing number of sequenced Neanderthal genomes has made it easier for researchers to filter out genetic changes that occurred in all or many Neanderthals. If these changes are found in modern humans, they could have physiological effects.
The researchers, Hugo Zeberg, Svante Pääbo, and their team, analyzed a gene more closely. Many people from South and Central America, as well as Europeans, have inherited a special Neanderthal variant of this gene. It is responsible for an ion channel that is responsible for pain sensitivity. The extensive study in the UK found that people who have the Neanderthal variant of the ion channel feel significantly more pain. Pain sensitivity depends on age. In direct comparison, people with a Neanderthal variant of the ion channel feel pain as if they were up to eight years older, according to experts. The special variant is available in three amino acids. Some amino acid substitutions do not affect the function of the ion channel. However, modern humans with a complete Neanderthal variant, including three of the amino acid substitutions, suffer from increased pain sensitivity, according to the researchers. The ion channel is more easily activated on a molecular level. Therefore, people who have inherited the Neanderthal ion channel have a higher pain sensitivity.
Svante Pääbo explains, “Today it is difficult to say whether Neanderthals felt more pain. Pain is modulated not only in the spinal cord but also in the brain.” However, the study has shown that the threshold for resolving pain impulses was much lower in Neanderthals than in many modern humans. The interbreeding of modern humans and Neanderthals has had a lasting impact on the pain sensitivity of their offspring.
