The ommatidia of amosRoi-1 mutant flies have variable numbers of cone cells (1-6 per ommatidium). The shapes and patterns of packing of these cone cells corresponds to the patterns of packing seen in aggregates of identically sized soap bubbles: a single cone cell is round; clusters of 2-5 cone cells all pack in the pattern primarily observed for a soap bubble aggregate of that number; clusters of 6 cone cells pack in one of the three stable configuration seen for soap bubble aggregates of that number.
Heterozygotes show a severe disruption of the ommatidial lattice in the retina. The ommatidia can contain either more or less than the normal number of photoreceptor cells (for example the small rhabdomeres characteristic of photoreceptor cells R7 and R8 can either be missing or clustered). Pigment cells are often missing, resulting in large clusters of photoreceptors that include the equivalent of 2 to 3 normal ommatidia. R8 precursors are irregularly spaced and show occasional twinning in third larval instar eye discs, and there is disorganised recruitment of other ommatidial cells. Homozygous clones in the retina are smaller than their wild-type twin spots and contain very aberrant photoreceptors with fused or distorted rhabdomeres. Wild-type clones in the retina in a heterozygous background develop into a regular array of normal ommatidia, while the surrounding heterozygous tissue develops into abnormal ommatidia. At the edge of the clone, mosaic ommatidia (containing both wild type and heterozygous photoreceptors) are usually abnormal in structure.
Eye facets of amosRoi-1/+ irregularly rounded, sometimes enlarged; eyes sometimes bulge. RK2A.
Adult eyes are rough with irregular round bulging facets. Variable number of rhabdomeres per ommatidia. Highly variable size and shape of clusters on eye disc.