Studies involving RNAi have shown that this mode of interference can function across cell boundaries; that is, the site of injection is not critical for successful gene inactivation [1]. As a result, it is also possible to initiate RNAi either by soaking worms in a solution of dsRNA or by feeding worms with Escherichia coli expressing target gene dsRNA, as RNA can be absorbed through the gut and distributed to somatic tissues and the germ line [3,4]. However, these other delivery systems have seen limited use in published studies as the observed efficiency of gene inhibition is significantly lower than with microinjection of adult hermaphrodite worms [5].
