The gene identified for grey hair is IRF4, which is known to play a role in hair colour; but this is the first time it has been associated with the greying of hair.
"We already know several genes involved in balding and hair colour but this is the first time a gene for greying has been identified in humans, as well as other genes influencing hair shape and density," says lead author, Dr Kaustubh Adhikari, UCL Cell & Developmental Biology.
Hair greying is caused by an absence of melanin in hair so the scientists want to find out IRF4's role in this process as it is involved in regulating production and storage of melanin.
They say that 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.
In their study, published in Nature Communications, the researchers 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.
"It was only possible because we analysed a diverse melting pot of people, which hasn't been done before on this scale. These findings have potential forensic and cosmetic applications as we increase our knowledge on how genes influence the way we look,” explains Adhikari.
Professor Andres Ruiz-Linares, UCL Biosciences, who led the study, adds that finding the first genetic association to hair greying could provide a good model to understand aspects of the biology of human ageing.
“Understanding the mechanism of the IRF4 greying association could also be relevant for developing ways to delay hair greying," he says.
Other genes identified
As well as this, scientists from the University of Bradford's Centre for Skin Sciences also found other genes as part of the study which influence a number of hair characteristics, such as curliness, shape, beard thickness and eyelash density.
One of these is the gene, PRSS53, which influences hair curliness.
"An enduring fascination of human evolution has been our peculiarly luxuriant scalp hair, and finding a new variation in the Protease Serine S1 family member 53 (PRSS53) gene provides an important insight into the genetic controls underpinning scalp hair shape and texture," says Professor Desmond Tobin, University of Bradford.
"The PRSS53 enzyme functions in the part of the hair follicle that shapes the growing hair fibre, and this new genetic variation, associated with straight hair in East Asians and Native Americans, supports the view that hair shape is a recent selection in the human family."
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."