Fig. 7. Headless phenotype of ey^D pharates and their partial rescue by inhibition of apoptosis. Scanning electron micrographs of the anterior portion (A-D,I,J) or left eyes (E-H) of pharate (B-D) or viable (A,E-J) adults of the genotype indicated are compared. Note that, in contrast to the headless phenotype of toy^hdl flies, the penetrance and expressivity of the headless phenotype of ey^D pharates is the same at 18°C and 25°C with about 50% of the pharates exhibiting no (B) or only few (C) structures derived from the eye-antennal discs, while the phenotype of most pharates is much stronger than that shown in D. The variability of heterozygous ey^D phenotypes (E-I) presumably reflects a strong influence of the genetic background as illustrated by the eyeless phenotype obtained after several generations of selections for small eyes (I). Expression of the baculovirus P35 protein, an inhibitor of apoptosis (Hay et al., 1994), in eye-antennal discs is able to rescue more than half of the homozygous ey^D flies to viable adults. These flies possess both antennae, no eyes, but usually all three ocelli (J). (A,B,J) Dorsal, (C,D-I) lateral views, anterior is to the left.