National Geographic : 2007 Sep
SCIENCE IN THE RED 2% of the world's population are estimated to be natural redheads. 13% of Scotland's population are redheads. Two out of five carry the gene. $123 million was spent on red hair dye in the U.S. in 2006. Red Alert Does Britain's Prince Harry have endangered roots? This year, news reports buzzed that true redheads will be extinct by 2100, since carriers of the carrot top gene are less and less likely to pair up in an age of global inter mingling (a child usually needs a copy from each parent to get the red result). But while redheads may decline, the potential for red isn't going away. When a mutation created the special gene in northern Europe millennia ago, its effect on hair and skin pigments-causing red to build up instead of brown-was beneficial, upping the body's ability to make vitamin D from sun light. Today, the gene's carriers are often prone to skin cancer and, oddly, some are more sensitive to heat- and cold-related pain. Only about 4 percent of people possess the gene, so fewer show the red trait. Still, it's hiding in the genome, rearing up far from its frigid origins, in far-flung places like Jamaica, a tip of the hat from a fiery Scottish forebear. -Jennifer S. Holland PHOTO:REBECCAHALE,NGSSTAFF.RED-DYEDATA:NIELSEN,COURTESYCLAIROL/PROCTER & GAMBLE ^" . I t-2.