Fig. 6. DMKP3 functions both in the R3/R4 pair and outside of the photoreceptors. (A) A section through a mosaic eye and a magnification and further examples of mosaic ommatidia in insets. Pigmented cells are Dmkp3⁺ (arrowheads), tissue devoid of pigment granules is Dmkp3^-. Cartoons represent the genotype with Dmkp3⁺ photoreceptors in red and Dmkp3^- cells in pink. (B) Quantitative analysis of 73 phenotypically Dmkp3^- mosaic ommatidia (cartoons to the left, compare to Fig. 5A) showing both Dmkp3^- (pink in the bar diagram) and Dmkp3⁺ photoreceptors (red) at any position. Data are from both males and females and absolute numbers are given above and below the chart, respectively. Genetically wild-type ommatidia exhibiting a Dmkp3^- shape can also be observed close to a Dmkp3^- clone (section through a male eye in C and insets). (D) Concordantly, an additional photoreceptor (blue) can differentiate into an R4 cell (red) even outside of a Dmkp3^- clone (marked by the absence of GFP, green) (higher magnification in E-H). The misdifferentiated cell is marked by an arrow. R4 cells (red) are also observed outside of ommatidial clusters (green) in a sev^S11 background (arrow in I-K) providing an explanation for the occurrence of extra outer photoreceptors in sev^S11 eye-sections (arrow in L).