Fig. 6. ife-1(RNAi) worms display temperature-sensitive sterility and reduced brood size. The F1 hermaphrodite progeny of mothers injected with ife-1 dsRNA or with water (control) were analyzed for sterility and brood size at (A) 16°C, (B) 20°C and (C) 25°C. The numbers of ife-1(RNAi) F1 worms analyzed were 14, 53 and 225 at 16°C, 20°C and 25°C, respectively. The numbers of control F1 progeny analyzed were 13, 13 and 14 at 16°C, 20°C and 25°C, respectively. At 25°C, 80% of RNAi worms did not produce any progeny. The remaining 20% of RNAi worms at 25°C and all RNAi worms at 16°C and 20°C produced a smaller number of progeny than control worms. (D) F1 males from matings between injected mothers and N2 males were grown at 25°C and tested for the ability to produce outcross progeny when mated with unc-32 or fem-2 animals. The number of ife-1(RNAi) and control males examined was 135 and 31, respectively. Of RNAi males, 85% did not produce any cross-progeny after mating. The remaining 15% of RNAi males produced a smaller number of cross-progeny than control males.