Cutting one gene makes files live six times longer, researchers find
Special to World Science
An experiment has resulted in one of the longest recorded life-span extensions in any organism and opened a new door for anti-aging research in humans, researchers say.
Scientists have known for several years that an extra copy of a gene called SIR2 can promote longevity in yeast, worms and fruit flies.
But now, scientists at the University of Southern California say removing the gene gives even better results: it makes fruit flies live up to six times longer than normal.
Researchers said they got the most dramatic improvement was found when they combined the gene removal with an extremely low-calorie diet and/or a mutation in one or two genes, called RAS2 and SCH9.
Experiments with human cells gave results consistent with these findings, the researchers said.
The researchers wrote a paper describing the fruit fly experiments to appear in the Nov. 18 edition of the research journal Cell.
Since all mammals share key aging-related genes, the paper points to a new direction for human anti-aging research.
The university’s Valter Longo, lead author of the paper, suggests that removing SIR2 may let an organism more easily go into a an extreme survival mode characterized by the absence of reproduction, improved DNA repair and increased protection against stress to its cells.
The long-lived organisms in Longo’s experiment showed extraordinary resilience under stress, he said. “We hit them with oxidants, we hit them with heat,” he remarked. Oxidants are a type of oxygen-containing chemical that damage cells.
Longo predicted that as molecular geneticists master the levers of aging, they will be able to design drugs that coax the body into entering chosen aspects of a starvation-response mode, such as stress resistance, even when food is plentiful.
If enough food is available, an organism might be programmed both to reproduce normally and to maximize its survival systems.
Longo urged caution in extrapolating the result to humans.
“We have been very successful with simple organisms,” he said. “Naturally, mammals are complex, and it will be a great challenge to get major life-span extension.”
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