That immediately came to my mind also. Apparently it's due to a variation of the MC1R gene which according to what I've read here, fourth paragraph [0], both de

That immediately came to my mind also. Apparently it's due to a variation of the MC1R gene which according to what I've read here, fourth paragraph [0], both developed independently of one another. Fascinating. 0) https://humanorigins.si.edu/evidence/genetics/ancient-dna-and-neanderthals/dna-genotypes-and-phenotypes https://humanorigins.si.edu/evidence/genetics/ancient-dna-an... Also it's not necessarily the reception of pain itself that's different, as someone else said, but the perception or anticipation of it [1] that changes the degree of anesthetization required. 1) https://www.verywellhealth.com/do-redheads-really-need-more-pain-medication-3157333 https://www.verywellhealth.com/do-redheads-really-need-more-...