The eyes of double mutants for sca1 and cnomis1 are extremely rough, accompanied by giant ommatidia, formed as a result of fusion. The bristle phenotype of sca1 is also enhanced by cnomis1 . Double mutant flies show supernumerary bristles. There is a genetic interaction between the two loci, also revealed by an examination of wing morphology. Double mutants have rumpled wings curved downward, with occasional shortening of the anterior cross vein.
Additonal interactions occur between cno and shaggy , armadillo , and myospheroid .
It is intriguing that the genes encoding proteins involved in adhesive cell-cell communications are shown to interact with cno . Proteins coded for by these genes mediate the adhesion of the different cell layers in a variety of developing tissues. Morphological studies of the fly's compound eye suggest that induction of photoreceptors, including the R7 photoreceptor, is unaffected by cno mutations. It has been suggested that R7 photoreceptors occupy unusual positions in pupal discs because the mutant discs fail to form a correct mesh of pigment cells, which shape ommatidia into regular hexagonal structures. A strong mutation in cno eliminates from one to three cone cells from most ommatidia.