Interfering with worms

In the 16 November Nature, Fraser et al. and Gönczy et al. present the first large-scale reverse genetic analyses of a multicellular organism (Nature 2000, 408:325-330; Nature 2000, 408:331-336). Fraser et al. use RNA-mediated interference (RNAi to target 2,416 predicted genes on chromosome I of the worm Caenorhabditis elegans by feeding the worms with bacteria expressing double-stranded RNA. Of the analyzed genes, 13.9% show a phenotype, increasing the number of sequenced chromosome I genes with a known phenotype from 70 to 378. The identified genes include 90% of known embryonic lethal genes from chromosome I, but only 45% of genes with known post-embryonic phenotypes, with genes involved in nerve and sperm cell function apparently resistant to RNAi. The majority (60%) of the phenotypes were embryonic lethal, including many genes involved in basic metabolism. The largest class of post-embryonic phenotypes are in the uncoordinated (Unc) class, which generally relate to neuromuscular ...