Science Daily: Neanderthals may have had a lower threshold for pain

"Pain is mediated through specialized nerve cells that are activated when potentially harmful things affect various parts of our bodies. These nerve cells have a special ion channel that has a key role in starting the electrical impulse that signals pain and is sent to the brain. According to a new study, people who inherited the Neanderthal variant of this ion channel experience more pain.

As several Neanderthal genomes of high quality are now available researchers can identify genetic changes that were present in many or all Neanderthals, investigate their physiological effects and look into their consequences when they occur in people today. Looking into one gene that carries such changes, Hugo Zeberg, Svante Pääbo and colleagues found that some people, especially from central and south America but also in Europe, have inherited a Neanderthal variant of a gene that encodes an ion channel that initiates the sensation of pain.
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Here is the paper: A Neanderthal Sodium Channel Increases Pain Sensitivity in Present-Day Humans

The SNPs are rs12478318 (G = Neanderthal variant), rs4369876 (A) and rs3750904 (C).