Who knew that the elixir of youth would ultimately be hidden in a poorly understood gene that not only fosters longevity but also enhances quality of life? Well, scientists in Britain have identified the gene that regulates lifespan in mammals, which could one day lead to treatments to hold off ageing and its related illnesses, 'The Guardian' reported today."Ageing is a major risk-factor for all diseases, heart disease, cancer, Alzheimer's. Intervening in the ageing process may capture and ameliorate a wide range of diseases," lead researcher Dominic Withers of the Centre for Research on Ageing at University College London was quoted as saying.In fact, the researchers identified the gene IRS-1 involved in regulating the function of insulin -- a hormone that controls the amount of sugar in blood -- after conducting experiments in mice.Findings in male mice showed that those without IRS-1 lived 20 per cent longer and had much healthier lives. Female mice without the gene had even better longevity, living 30 per cent longer on average.Moreover, the mice without IRS-1 were much healthier than normal mice as they aged -- they had brighter eyes, better immune function and healthier skin and bones."The results suggest that IRS-1 is a pathway conserved by evolution that regulates the lifespan of mammals, and it may point to methods of potentially delaying ageing in humans," Prof Withers said.David Gems, another of the study's authors, said the work on IRS-1 in mice was the first to show that mammals could stay healthy as they lived longer."Obviously, it's much harder to study these mechanisms in humans because our life expectancy is so much longer, but this study and our other work on ageing are laying crucial scientific groundwork," he said.