They are various shades of grey, but George Clooney, Richard Gere and Gary Lineker share one thing in common, a scientific study suggests – a genetic predisposition for a silver fox.
Scientists have discovered the first gene for turning hair grey and in the process revealed that some men, and women, are probably born with an inherited tendency to go grey before their time.
Hair colour is determined by what kind of melanin pigment is deposited in each hair shaft as it grows, but this hair-colouring process breaks down with age which is why grey hair is associated with advanced years.
However, not everyone goes grey as the same age and scientists believe that some people inherit a predisposition for turning grey as early as in their 20s or 30s. A study has now found the first gene likely to be involved in premature greyness.
“We have found the first genetic association to hair greying, which could provide a good model to understand aspects of the biology of human ageing,” said Professor Andreas Ruiz-Linares of University College London, who led the study published in Nature Communications.
The researchers found the gene, known as IRF4, by analysing the genomes of 6,357 people from a cohort of genetically-diverse volunteers who live across five countries in Latin America – Brazil, Colombia, Chile, Mexico and Peru. They included people with European, African and native American ancestry.
The IRF4 gene was already known to be involved in hair colour because it regulates the production and storage of melanin. But this was the first time that scientists had shown it to be directly involved in conferring a tendency to go grey in both men and women.
Given the amount of effort both sexes put in to covering up grey hairs, Professor Ruiz-Linares said that the identification of the first “grey gene” may help to develop more permanent ways of ridding the head of stray greys.
“Understanding the mechanism of the IRF-4 greying association could also be relevant for developing ways to delay hair greying,” he said.
The study also looked at other aspects of human hair, such as hair shape, balding, beards, eyebrow thickness and “monobrow” – when the two eyebrows fuse together into a single line.
But it was the investigation of hair colour that led to the first grey gene, said Kaustubh Adhikari of UCL, the study’s lead author.
“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,” Dr Adhikari said.
“It was only possible because we analysed a diverse melting pot of people, which hasn’t been down been done before on this scale. These findings have potential forensic and cosmetic applications as we increase our knowledge of how genes influence the way we look,” he said.
It may in future be possible, for instance, to build up an ID picture of a crime suspect by analysing a drop of blood left at the scene of a crime.
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