Heterozygotes have a wild-type eye phenotype. Ommatidial cluster formation in mosaic eye discs (in which some cells have lost the P{lacW} insertion in DrMioP10) is always significantly increased within posterior patches of Ecol\lacZ-positive cells (these cells carry DrMioP10). In discs with large patches of Ecol\lacZ- cells (which have lost the P{lacW}DrMioP10 insertion) cluster formation is blocked to a level observed in DrMio eye discs, demonstrating that the dominant mutation acts autonomously.
Revertant. Selected as: a mutation resulting in suppression of the DrMio/+ eye phenotype.
Excision of the P{lacW} element results in the recovery of the dominant eye phenotype of the DrMio progenitor, indicating that the P{lacW} element in DrMioP10 mediates the suppression of the eye phenotype.
Remobilization of the P-element resulted in reversion to the dominant small eye phenotype.