Worm and yeast genes shed light on ageing

Several of the genes that influence lifespan in a type of worm do the same job in yeast, say US researchers, suggesting that they may also be involved in human ageing. A team based at the University of Washington in Seattle has discovered that 25 of the 276 genes that affect ageing in the tiny soil-dwelling nematode worm also affect the lifespan of yeast. The scientists, published in the journal Genome Research, also found that 15 of the genes have human equivalents.

'Nematodes and humans are more similar to each other on an evolutionary scale than nematodes and yeast', explained Dr Erica Smith, first author of the study, adding 'we reasoned that if a particular gene modulates ageing in both yeast and nematodes, there is a good chance that gene plays a similar role in people'. The researchers first trawled through previous studies to draw up a list of genes thought to affect nematode lifespan, then looked for highly similar genes in yeast. They then analysed the yeast genes individually, to see which shortened the life of the microbe.

The team found that many of the aging genes shared between the two species were involved in processing nutrients, suggesting that similar biological pathways are involved. 'This finding indicates that two very different species age through overlapping mechanisms and suggests that these mechanisms are likely to also contribute to human aging', said study leader Dr Brian Kennedy.

It has long been know that drastic 'very low calorie' diets can lengthen the life of mice and other animals - a fact that scientists are trying to exploit to develop anti-ageing drugs. Matt Kaeberlein, a co-author on the paper, said: 'Most people don't want to cut their diet that drastically, just so they may live a little longer. But some day in the future, we may be able to accomplish the same thing with a pill'.

The team are now repeating their experiments in mice, to see if the same genes that affect longevity in worms and yeast have the same effect in mammals. However, Kennedy sounds a note of caution, saying 'it's probably easier to extend lifespan dramatically in a worm or yeast than in a mammal, because the mammals are a more complex organism'.