Does not appear to have a gross defect on brain development.

The R2/R5 precursor pair is transformed into R3/R4 in most preclusters in homozygous third larval instar eye discs. The overall arrangement and rotation of the clusters is abnormal, with some clusters rotating in the wrong direction and others not rotating. Mosaic ommatidia with mutant R3 and R4 cells behave like wild-type with respect to ommatidial polarity.

e⁴ wo¹ ro¹ mutant larvae show an abnormal response to UVC radiation.

The ommatidial array is disrupted and the number of photoreceptor cells per ommatidium is variable.

Disrupts an early stage of eye development: ommatidal array is disrupted, number of photoreceptors per ommatidia is variable.

Homozygotes have rough eyes; slightly smaller and narrower than wild type. Approximately normal numbers of facets but arrangement irregular; frequently have fewer and sometimes more than eight retinula cells; some facets missing such that three ommatidial bristles juxtaposed; other facets fused (Stemm-Tegethoff and Dicke, 1974; Ready, Hanson and Benzer, 1976). Fiber pathways through lamina and into medulla in considerable disarray; optic chiasma between the two replaced by parallel fibers; laminar cartridge and medullar columns deranged, ventral epithelial nuclear row absent; medulla displaced from normal position and rotated anteriorly. Mosaic studies demonstrate that phenotype is eye autonomous; i.e., the genotype of the eye dictates that of the underlying nervous elements.

ro¹ is an enhancer of eye phenotype of Scer\GAL4^sca-109-68, ato^UAS.cJa

ro¹ is an enhancer of ommatidium phenotype of Scer\GAL4^sca-109-68, ato^UAS.cJa