When expression is driven by Scer\GAL4GMR.PS the eyes are roughened. Ommatidia and interommatidial bristles are irregular. Two copies of DrefCR3.Scer\UAS cause ommatidia to fuse. The phenotype is more pronounced than for DrefCR1.Scer\UAS. Examination of BrdU incorporation indicates the S phase zone for the second mitotic wave posterior to the morphogenetic furrow is reduced.