Fig. 6. ed is required in the R8 equivalence group to prevent R8 twinning. Mosaic analysis of ed alleles examined by confocal microscopy for immunohistochemical detection of Sens (red), Boss (blue) and nlsGFP (green) in third larval instar eye imaginal discs. The mosaic clone is distinguished by the absence of nlsGFP and the border has been marked with a white line. (A) ed^6.1 homozygous clone. (A) Overlay. (A') Red channel. (A'') Blue channel. A mixed twin of a mutant and a wild-type R8 at the clone border has been marked by an arrow. (B) ed^4.4 homozygous clone. (B) Overlay. (B') Red channel. (B'') Green channel. An R8 twin consisting of two wild-type cells at the clone border is marked with an arrowhead.