Deleting a gene thought to extend lifespan has counterintuitively yielded the longest recorded life extension in any organism.

An extra copy of the gene, SIR2, promotes longevity in yeast, worms and fruit flies, a finding that has driven longevity-oriented drug-development.

Reporting in the journal Cell, molecular geneticists at the University of Southern California have now found evidence that SIR2 may also promote aging.

Rather than adding copies of SIR2 to yeast, Valter Longo and colleagues deleted the gene altogether.

The result: a lifespan up to six times normal when the SIR2 deletion was combined with caloric restriction or a mutation in one or two genes, RAS2 and SCH9, that control storage of nutrients and resistance to cell damage.

The effect was also seen with human cells, although this wasn’t reported in the Cell paper.

More here.