A 'younger gene' has been identified by scientists with black people twice as likely to have it than their white counterparts.

Harvard scientists led a study involving almost one million people with private genetic database 23andMe and found one in ten white and a fifth of black Americans carry the 'genetic recipe' for youthful skin.

Researchers working on Olay's largest ever study, believe its presence can result in people looking up to 10 years younger than they actually are.

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Age defying: Halle Berry, pictured here at the Golden Heart Awards, looks far younger than her 48 years

The discovery could explain the youthful appearance of celebrities such as the actress Halle Berry, 48, and the model Iman, 59, wife of musician David Bowie.

The findings are being presented this week at the World Congress of Dermatology in Vancouver, Canada, The Sunday Times reports.

The genes fit into seven categories that affect areas such as DNA repair and the performance of the skin's barrier against damaging environmental factors.

Young genes? Model Iman is well-known for her youthful looks as scientists suggest this could be down to her gene pool

Youthful looks: British actress Emma Thompson looks great at 56 and has made no secret of her dislike for cosmetic surgery

Researcher Alexa Kimball, professor of dermatology at Harvard Medical School, said: 'Many of us felt that people with darker skin aged better because of more pigment and better photo [sunlight] protection, but we have found there is much more to it than that.

'They have other characteristics in their skin which confer good ageing, which until now we had no idea about.'

The search for youthful looks has spawned a multibillion-pound cosmetics industry and increasing use of Botox.

'What's exciting about these findings is that the genes that make up the unique skin fingerprint of 'exceptional skin agers' may hold the key to successful ageing,' said Dr Rosemarie Osborne, a beauty research fellow for Procter & Gamble.

'Decoding which pathways they affect, and understanding why they are acting differently in these women, ' nature or nurture', can enable Olay researchers to help more women achieve skin that looks like the exception, not the rule, at any stage of life.'

The drug works by temporarily paralysing the muscles that create wrinkles. Liz Hurley, Lulu, Meg Ryan and Leslie Ash are among those who have had botulinum injections to get rid of facial lines.

British actress and Oscar-winner Emma Thompson is a well-known critic and even formed the 'British Anti-Cosmetic Surgery League,' with Kate Winslet and Rachel Weisz, making a pact never to dabble in plastic surgery or other treatments.

But this project suggests they could be amongst the lucky few with the genetic recipe to naturally keep them young-looking.