Researchers have identified ten genetic variants linked to hair traits, including the rate at which hair goes grey and whether a person will have a 'monobrow'.

Previous studies looking at European and East Asian populations have identified genes associated with male-pattern baldness, hair colour and curliness. Kaustubh Adhikari at University College London and his colleagues studied the genomes of more than 6,000 people living in Brazil, Colombia, Chile, Mexico and Peru, categorizing volunteers according to the colour, shape and pattern of hair on their scalp and faces.

They found, for example, that the variant associated with the rate of hair-greying is in a gene called IRF4, which regulates the production and storage of melanin — the pigment that determines hair, skin and eye colour. A variant of FOXL2 is linked to eyebrow thickness, and a PAX3 variant is associated with the growth of a monobrow.

Nature Commun. 7, 10815 (2016)