It has been known for several years that an extra copy of the SIR2 gene can promote longevity in yeast, worms and fruit flies. Many thought the gene could promote longevity. However, some molecular geneticists now suggest that SIR2 actually promotes aging.

Six Times the Normal Lifespan

A new experiment, rather than adding copies of SIR2 to yeast, deleted the gene altogether. The result was an extended lifespan -- as much as up to six times longer than normal -- when the SIR2 deletion was combined with caloric restriction or a mutation in one or two other genes.

Could be the Same in Humans

The behavior of human cells with reduced SIR2 activity also seem to confirm that SIR2 has a pro-aging effect. This could point to a new direction for human anti-aging research.

Extreme Survival Mode

It is theorized that the gene may block organisms from entering an extreme survival mode characterized by improved DNA repair and increased protection against cell damage. Organisms normally enter this mode in response to starvation.

Cell November 18, 2005; 123(4): 655-667University of Southern California November 17, 2005

Dr. Mercola's Comment: