Neanderthals may have had a weak pain threshold

July 23 (UPI) -- A new genomic analysis suggests Neanderthals may have had a lower threshold for pain.

Scientists found some modern humans -- mostly in central and south America, but also in Europe -- have inherited the Neanderthal variant of the pain-related gene.

The gene influences the function of an ion channel that initiates the sensation of pain, researchers say.

The discovery, detailed Thursday in the journal Current Biology, was made possible by several breakthroughs in genomic science.

Over the last year, scientists have collected and sequenced three Neanderthal genomes of especially high quality. The genomic data allowed scientists to identify gene variants that were likely present in most Neanderthals.

"This is really what made this possible," study co-author Svante Pääbo told UPI in an email.

"These high-quality genomes were made possible by many large and small technical advances over the past ten years, involving how we extract the DNA, convert it to DNA libraries and map it to the the human genome," said Pääbo, a researcher at the Max Planck Institute for Evolutionary Anthropology in Germany.

Researchers used the new data to identify Neanderthal gene variants that are found in modern humans. The pain-related gene variant stood out because it codes for three amino acid differences, researchers said.

"[The gene] is unusual in having three differences unique to Neandertals in the protein it encodes," Pääbo said.

Using data from a large population study conducted in Britain, researchers determined that this particular gene variant influences the experience of pain.

As people age, their pain threshold gets lower. In the study, people with the gene variant reported pain thresholds consistently similar to people eight years older.

In modern humans, the three amino acids encoded by the gene variant cause the ion channel to remain open longer after stimulation, increasing the odds that a pain impulse will register in the nerve.

Because pain is also controlled in both the spinal cord and the brain, researchers can't be certain whether this gene variant caused Neanderthals to have a lower pain threshold.

The authors of the latest study are currently working to examine the impacts of other Neanderthal gene variants, including variants related to fertility and susceptibility to infections.