Fig. 4. vri loss of function allele reduces eye size, alters morphology and size of ommatidia and photoreceptors. Scanning electron micrographs of vri clonal eye were generated by the EGUF/hid method. Photoreceptor cells bearing the dominant photoreceptor cell lethal transgene GMR-hid die during metamorphosis. The l(2)CL-L1 recessive cell lethal mutation leads to lethality at an earlier stage of eye development. The crosses were performed at 29°C and the eyes were observed in males. (A,C,F) vri⁺ FRT40A/vri⁺ FRT40A control eyes from [ry⁺ hs-neo FRT]40A/[ry hs-neo FRT]40A GMR-hid l(2)CL-L1; ey-GAL4 UAS-FLP/+ flies. (B,D,G) vri^5R7.2/vri^5R7.2 clonal eyes from vri^5R7.2[ry⁺ hs-neo FRT]40A/[ry hs-neo FRT]40A GMR-hid l(2)CL-L1; ey-GAL4 UAS-FLP/+ flies. (B) Clonal eye smaller than control (A) and with a rough aspect. (C,D) The ommatidia are disorganized and present an abnormal morphology. They are spherical rather than hexagonal and bristles are missing or atrophic. (E) The number of ommatidia is reduced in vri clonal eyes. Values are mean numbers of ommatidia (±s.e.) observed in male eyes. The mean number of ommatidia is reduced by 10% in vri⁵, 17% in vri¹ and 19% in vri^5R7.2 eyes compared with the vri⁺ control eyes (Student's test: P<0.001). (F,G) Longitudinal sections through adult retinas. (G) Clonal retina with photoreceptor stalks twisted and shorter than control (F).