of par-3 resulted in 100% embryonic lethality for all injected worms (n = 9), worms subjected to RNAi of par-3 by feeding resulted in 100% dead embryos in 16/24 cases but lower levels of lethality (on average 88%) in 8/24 cases (data not shown). The overall comparison shows that RNAi by feeding is of similar strength to RNAi by injection for maternal-effect embryonic lethal genes. For some genes, however, RNAi by feeding appears to be somewhat more variable than RNAi by injection.
