NausAllien Posted June 7, 2022 Posted June 7, 2022 On 6/6/2022 at 6:41 AM, sugarysunflower said: Why does Sam's beard hair colour not match the head hair colour? Because that's how genetics work. A mutation in the melanocortin-1 receptor found on chromosome 16 is what causes hair to be red. If only ONE of the two chromosomes has the mutation, then only the beard will be red. For hair to be red, both chromosomes must have this mutation. This is the reason why redheads are extremely rare (1-2% of the population) but men with red beards aren't.
sugarysunflower Posted June 7, 2022 Posted June 7, 2022 1 hour ago, NausAllien said: Because that's how genetics work. A mutation in the melanocortin-1 receptor found on chromosome 16 is what causes hair to be red. If only ONE of the two chromosomes has the mutation, then only the beard will be red. For hair to be red, both chromosomes must have this mutation. This is the reason why redheads are extremely rare (1-2% of the population) but men with red beards aren't. Thank you so much!! Also just read that humans with natural red hair have elevated basal pain thresholds and an increased sensitivity to opioid analgesics (melanocyte dependent but melanin independent). I’m guessing this is an evolutionary advantage to the colder environments where people with red hair tend to be located. fascinating ! thank you!!
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