Scientists may have hit upon a new way of extending the lifespan of living organisms - by activating a gene that destroys unhealthy cells.

Researchers at the University of Bern found they were able to help flies live up to 60 percent longer by increasing the activity of a gene that targets damaged cells. If this could be transferred to humans, it could extend the average lifespan of people in developed countries like the US and the UK to beyond 120 years old. The scientists found that a gene called ahuizotl, or ‘azot’ acts like a sort of cellular quality control, helping to weed out unhealthy or malfunctioning cells.

It is thought to help protect crucial organs like the brain or the gut from a build up of potentially harmful unhealthy cells. When the scientists gave fruit flies an extra copy of this gene, they found the insects’ tissues became healthier and aged slower. Humans are known to also have the azot gene, opening up the possibility that it could be used to create new anti-ageing treatments. Dr Christa Rhiner, a lecturer in cell biology at the University of Bern who took part in the study, said: ‘Our flies had median lifespans 50 to 60 per cent longer than normal flies.’

For centuries, humans have been seeking ways to extend their lives. In the Old Testament, Methuselah was said to have lived for 969 years. Medieval Knights went on quests to search for the Holy Grail, which was said to bestow powers including extended life. Alchemists also dedicated themselves to producing the Elixir of Life. Some scientists have speculated that the human lifespan could be extended to up to 200 years. Currently the oldest person in the world is Leandra Becerra Lumbreras, a Mexican woman who claims to be 127 years old, although she has apparently not got any evidence to support when she was born. However, this latest research is still some way from being tested in mammals. The scientists were able to extend the lifespan of fruit flies by genetically engineering them to have three copies of the azot gene. There are normally two copies of this gene in each cell.

The gene is named after a mythological Aztec creature that selectively targets fishing boats to protect the fish population of lakes. Eduardo Moreno, who led the work at the Institute of Cell Biology from the University of Bern, said: ‘Our bodies are composed of several trillion cells and during aging those cells accumulate random errors due to stress or external insults, like UV-light from the sun.

‘Because some cells are more affected than others, we reasoned that selecting the less affected cells and eliminating the damaged ones could be a good strategy to maintain tissue health and therefore delay aging and prolong lifespan.’ Dr Aubrey de Grey, a leading researcher on gerontology and the Chief Science Officer of the SENS Research Foundation, which aims to use regenerative medicine to extend human lifespan, said it remained to be seen if the approach had any therapeutic applications.

But, he added: ‘The lifespan results reported here provide good reasons to explore that possibility further. ‘This study significantly advances our understanding of a mechanism of cellular quality control that detects relative, rather than absolute, cell health. ‘Preserving the healthier cells in a particular tissue and culling the sicker ones irrespective of the whole tissue’s average health is a strategy that evidently works well in many circumstances, since it also exists in mammals.’