Mosaic experiments, involving induced mitotic recombination in rap1/+ larvae, showed that normal adult ommatidia always had a rap+ R8 cell, whereas R1-7 could readily be genotypically rap1 in such facets; also, certain phenotypically mutant ommatidia, near borders separating mutant and wild-type tissue, contained all rap+ cells (in clusters of 3, 4, 6, or 8 photoreceptor cells). rap1 was shown to complement the nearby rough-eye mutation, rg.
hypomorph?
Allelic series in order of ascending strength rap1 < rape2 = rape4 = rape6, rapx-2 < rap3 = rapx-3.