Scientists for the first time have identified the gene responsible for the process of hair losing its colour and turning grey.

The study, which was led by researchers at University College London, also found genes relevant to dense eyebrows and beards.
Dr Kaustubh Adhikari author on the study said that "this is the first time the gene for greying hair had been identified" adding that "we already know the several genes responsible for hair colour and balding but not that of shape and density".

Published in Nature Communications, the study analysed a population of over 6,000 people with varied ancestry across Latin America to identify new genes associated with hair colour, greying, density and shape, i.e. straight or curly.

The gene identified for grey hair -- IRF4 -- is known to play a role in hair colour but this is the first time it has been associated with the greying of hair. This gene is involved in regulating production and storage of melanin, the pigment that determines hair, skin and eye colour.

Hair greying is caused by an absence of melanin in hair so the scientists want to find out IRF4's role in this process. Understanding how IRF4 influences hair greying could help the development of new cosmetic applications that change the appearance of hair as it grows in the follicle by slowing or blocking the greying of hair.

The scientists found additional genes associated with hair including EDAR for beard thickness and hair shape; FOXL2 for eyebrow thickness and PAX3 for monobrow prevalence.
"It has long been speculated that hair features could have been influenced by some form of selection, such as natural or sexual selection, and we found statistical evidence in the genome supporting that view," added Dr Adhikari. "The genes we have identified are unlikely to work in isolation to cause greying or straight hair, or thick eyebrows, but have a role to play along with many other factors yet to be identified."