People with red hair have long been the butt of unfair jokes, but a study suggests that when it comes to ageing they may have the last laugh.
Dutch scientists have discovered that a gene which keeps people looking young is the same gene responsible for red hair and fair skin.
Researchers at Erasmus University in Rotterdam studied the faces of almost 2700 elderly Dutch Europeans and found that those carrying a variation of the MC1R gene, which influences skin colour, looked on average two years younger than they were.
MC1R is known to play a part in other biological processes, such as inflammation and DNA damage repair, which may be why it is linked to youthful looks. Professor Dr Manfred Kayser, who co-wrote the study, said: "For the first time a gene has been found that explains in part why some people look older and others younger for their age.
"Looking young for one's age has been a desire since time immemorial. The desire is attributable to the belief that appearance reflects health and fecundity."
The findings are particularly good news for redheads, as the data suggests they may be ageing slower and therefore be healthier. Perceived age has been shown to predict a person's health and mortality, suggesting that the age we perceive a person to be from the appearance of their face might also be related in important ways to a person's biological age and health.
During the study, published in the journal Current Biology, front and side images of the participants' faces were analysed by a 3D image assessment system.
It looked for more than 25 criteria, such as pigmented spots, wrinkles, skin tone and face shape.
This information was then subjected to an algorithm, which came up with a perceived age.
Kayser said that understanding the molecular biology of perceived age would be vital in identifying new ageing therapies, among other purposes.
"Our study provides new leads for further investigating the biological basis of how old or young people look," he said.
The association between the MC1R variant and perceived age found by the Erasmus University study has been replicated in two independent cohorts, including a study of 530 middle-aged French women, which also found links between the gene to skin ageing.
The authors of the latest research said more investigation is needed to identify precisely how specific features, such as skin sag or skin repair, could be linked to MC1R.
Dr David Gunn, of Unilever, which participated in the study, said: "The perception of age is one of the best and most exciting ways to measure how well people are ageing, which we hope will lead to further breakthroughs in health and ageing research in the near future."