Molecular genetics of life span in C-elegans:: how much does it teach us?

Several loci have been identified in the nematode worm Caenorhabditis elegans that, when mutated, can increase life span. Three of these genes, age-1, daf-2 and clk-1, have note been cloned. Mutations in these three genes are highly pleiotropic and affect many aspects of worm development and behaviour. age-1 and daf-2 act in the same genetic pathway and have similar effects on the worm. age-1 encodes a homologue of the p110 subunit of phosphatidylinositol 3-kinase and daf-2 encodes an insulin receptor family member. clk-1 encodes a protein of unknown biochemical function similar to the yeast metabolic regulator Cat5p/Coq7p. The implications of these findings for our understanding of organismal ageing are discussed.