Four different methods were compared to determine optimal induction conditions for RNAi; non-induced (Non-Ind) bacteria were also included for comparison. Induction conditions (Ind) were as follows: (1) Bacteria were induced on plates with IPTG at room temperature overnight; (2) bacteria were induced in culture at 37°C for 2 h; (3) bacteria were induced on plates with IPTG at 37°C overnight; (4) bacteria were induced in culture at 37°C overnight (see the Materials and methods section for detailed protocols). gpb-1, par-1 and par-3 were scored for percentage of dead embryos, unc-22 was scored for percentage of worms with an uncoordinated phenotype. Data shown represent the progeny of three fed worms. ND, not done; n is the number of worms or embryos scored; %Phe, percentage of worms or embryos with phenotype.