Somatic clones of rno² homozygous cells in the arista cause its transformation into a leg-like structure. Homozygous mutant ommatidia form an extra photoreceptor in 32.5% of cases. Occasionally mutant ommatidia have 2 extra or one less photoreceptor than wild-type (average number of photoreceptors per ommatidium is 8.4 compared to the normal 8.). Some ommatidia with extra photoreceptors are genotypically wild type, showing that this phenotype can occur through a non-cell-autonomous mechanism. Marker expression analyses suggest that the extra photoreceptors are R3/4 like, and also reveal additional cone cells and pigment cells: rno² mutant eye clones contain 4.4 cone cells, 2.2 primary pigment cells, and 5.3 secondary/tertiary pigment cells per ommatidium while wild-type control clones contain 4.0, 2.0, and 4.0, respectively. Including the photoreceptors, the total number of cells per ommatidium is 18.0 for the wild type and on average 20 for rno² mutant clones. There is a dramatically less cell death in rno² homozygous clone cells in pupal eye discs at 50 hours after puparium formation, compared to wild-type.

rno²/rno[+] is a suppressor of eye phenotype of ebi^1-334.GMR