What’s the genetics behind redheads, gingers, carrot tops, strawberry blondes, and other bearers of the world’s rarest hair color (not including neon green)?
A genome-wide study of 350,000 people, the “largest genetic study of human hair color” to date, has sought to unravel the genetic mysteries of inheriting locks, whether they’re red, blonde, black, or brown.
It was previously believed that red hair is inherited through two versions of the MC1R gene, one from your mom and one from your dad. However, the new research suggests that MC1R accounts for just 73 percent of heritability for red hair. Furthermore, the majority of people who carry two red-haired variants of the MC1R have brown hair or blonde hair.
As published in the journal Nature Communications, the new research suggests that at least eight different genes are responsible for red hair. Things are a little more complex for people with blonde or brown locks, with almost 200 genes contributing to the pigmentation of their hair.
The team also found that 12.7 percent of females in the UK have blonde hair and 5.2 percent have red hair, while 9.9 percent of males have blonde hair and 3.7 percent have red hair.
The color of your hair, as well as the color of your skin and eyes, all depends on the amount and type of melanin produced by your melanocytes. The nature of your melanocytes, in turn, is determined by your genes. Along with other types of melanin, red hair usually contains high amounts of pheomelanin, which has a pinkish-red hue and is particularly concentrated in the lips, nipples, and genitals. On the other hand, dark hair usually contains more eumelanin.
The researchers, from the University of Edinburgh in Scotland and Oxford University, reached their findings by sifting through the UK Biobank, a huge and unique genetic study of half a million people of European descent in Britain. That might sound limited at first, but the researchers argue the European population has some of the greatest natural variation of hair color in the world.
“Once again collaborative research is helping to provide answers to some of life's important questions,” Melanie Welham, executive chair of the Biotechnology and Biological Sciences Research Council (BBSRC), who helped fund the research, said in a statement.
“BBSRC is pleased to have helped support the largest genetic study of human hair color. It has provided some fascinating insights into what makes us such distinct individuals.”