What Makes Us Tick?

A mutant Caenorhabditis elegans worm, defective in the gene clk-1 , lives an extraordinarily long time. In this issue, Ewbank et al . (p. 980 ) report the sequence of clk-1 and find that it is homologous to the yeast gene CAT5/COQ7 , whose product regulates the transcription of genes that control yeast metabolism. In his Perspective, Guarente describes how these findings fit into a model of aging in which life-span is determined by the accumulation of damage to the organism, perhaps at a rate proportional to metabolism, and the counteracting repair of such damage.