It looks like genes will keep you in your jeans till kingdom come. The buzz is that a nematode worm holds the key to eternal youth. Researchers at the Salk Institute for Biological Studies, California, have identified a gene that links calorie restriction to longevity. The over-expression of a gene, encoding the protein PHA-4, led to increased lifespan in worms. This might lead to development of drugs that mimic the effects of calorie restriction.