And I don’t know why redheads. I mean, it’s not like: Oh, you have mouse brown hair, I won’t talk to you. I always want to know more, so I asked scientists.
In the late 1990s, scientists discovered that gene mutation causes red headedness. Specifically, it’s a variant of the melanocortin 1 receptor (MC1R), one of the key proteins that determines hair and skin color. The mutated gene is recessive, so in order for someone to have red hair, she has to inherit two copies of the gene, one from each parent. Lots of people, especially those with Northern European ancestry, carry one copy of MC1R, but relatively few carry the two copies required for flaming tresses. Red hair can occur in any ethnicity, but the greatest concentration of redheads originates in Northern Europe, near the U.K. Scotland has the highest percentage of natural redheads, with 13 percent and Ireland is a close second, with 10 percent. Only about 2 percent of people in the United States have naturally red hair.
If red hair is so rare, why does it occur so often in the same geographic area? Some biologists think that it’s an evolutionary adaptation. In cold and dark climates, fair coloring lets the skin absorb more light, which encourages the body to retain heat and produce more vitamin D. Also, for most of human history, people didn’t stray very far from the place where they were born and intermarried with people with similar genetic traits. When there were plenty of people carrying the gene, their children were very likely to get two copies of the mutated MC1R. Now that people migrate more, carriers of MC1R are more likely to intermarry with non-carriers. That’s good for genetic diversity, but maybe not so good for the survival of redheads in general.
Redhair and pain
The mutated MC1R gene has some other surprising effects. Although doctors and medical practitioners have long speculated that redheads were harder to sedate, a recent study from the University of Louisville determined that redheads really do require more anesthesia during surgery.
The researchers ran an experiment where they put women under sedation, and then tested their response to pain. The redheaded patients required 20 to 30 percent more anesthetic than other women to achieve the same level of sedation. Scientists at the university also tried to replicate the experiment with mice, and found that animals with a MC1R mutation required more sedation, too. They theorize that the mutated gene somehow has implications beyond hair color, and perhaps affects hormones or enzymes involved in our neurological system.
Redhair and beauty
|Actress Jessica Chastain|
I don’t mind spending a few minutes looking at miss Chastain’s hair. When my wife and I were still in the writing-love-letters of our relationship to be, I could spend the whole evening with her on the floor and me behind her on the couch just to envelop (is that the right word?) her hair. I couldn’t get enough of it.
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