Fig. 5. Effect of N induction in eyg null mutant. N^act was induced by ey-GAL4 (abbreviated as ey> N^act) in eyg^M3-12 homozygous mutant background. (A) Eighty percent of the pharates have head with no eyes. (B) Twenty percent have partially restored eye. (C) A few flies have a duplicated antennae. (D-F) The antennal discs are restored in size and have eyg-lacZ expression (green). (F) A disc has triplicated antennal fields (indicated by the eyg-lacZ expression). Occasionally one of the antennal fields can be recognized morphologically but lacks eyg-lacZ expression (not shown). (D-F) The endogenous eye field (based on the location of the optic stalk and Bolwig nerve; arrow) is highly reduced, lacks eyg-lacZ expression and has no photoreceptor differentiation (ELAV-staining, red). (D,E) In about 36% of the clones, an extra eye field (arrowhead) is induced dorsal to the endogenous eye field. The extra eye field can have eyg-lacZ (green) expression and photoreceptor differentiation (ELAV, red). The ocellus is marked by ELAV (^*). (G) The eyg-lacZ expression pattern (green) in wild type is used for comparison.