Genetics and the Unibrow
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Genetics and the UnibrowMy mom used to say I was going to give her grey hair, but she should have blamed her melanin levels. Melanin is the pigment in hair. Now scientists have identified eighteen new genes determining when you turn gray - and who gets a unibrow, curly hair, or resembles a werewolf by three in the afternoon.

Now we know why there’s such a variation in hair qualities. And collectively, we care just which variety we end up with, which is why $83 billion dollars is spent globally every year on hair products alone.

The study, to identify genes responsible for hair, involved a GWAS – a genome wide association study - in people of mixed European, Native American and African ancestry. GWAS is a rapid method to scan genomes for markers of genetic variations associated with diseases or other traits.

Now, for the first time a gene for graying hair has been identified. That gene is called IRF4, which affects another gene called TYR, and certain versions of it lead to reduced melanin - which causes gray hair.

Another gene called EDAR affects hair follicle density, particularly for beards, and in different populations, EDAR also determines hair shape. For curly hair in Europeans, look to a gene called trichohyalin; blame your thick eyebrows on the forehead box L2 gene; and the unibrow is the responsibility of the paired box gene 3. All told, eighteen new genes are responsible for the hair we live with.

But as we further understand how these genes function, maybe one day we could stop our hair from graying or our beards from sprouting and even order up some Shirley Temple curls.

For more information…

Study finds first genetic links for gray hair, beard thickness, and unibrows
Ever wonder why your hair goes gray? Researchers have long known that a slowdown in the production of melanin, the pigment that colors hair, is to blame...

A genome-wide association scan in admixed Latin Americans identifies loci influencing facial and scalp hair features
Nature Communications 7, Article number: 10815 doi:10.1038/ncomms10815

Genome-Wide Association Studies
A genome-wide association study is an approach that involves rapidly scanning markers across the complete sets of DNA, or genomes, of many people to find genetic variations associated with a particular disease...