The GlDN sensitized screen in the adult eye. (A) Schematic of the screen in which UAS-GlDN males were mutagenized and crossed to GMR-GAL4 virgin females. In the F1 generation the flies were scored for any enhancement or suppression of the eye phenotype caused by over-expression of GlDN. (B-D) Scanning electron micrographs of adult eyes. (B) w; UAS-GlDN, showing a wild type eye with a regular array of ommatidia and bristles. (C) Gl1/+ exhibiting a roughened, smaller eye. (D) w; GMR-GAL4/UAS-GlDN (abbreviated to GMR>GlDN throughout) showing the much reduced and disorganized eye phenotype used as the basis for the screen. (E) shows the effects of a dominant suppressor (SG13/+) on the phenotype in (D), and (F) shows the effects of a dominant enhancer (EG37/+). (G) Gl1/+; EG162/+, showing an enhanced phenotype than for Gl1/+ alone depicted in (C).