L1 mutant flies exhibit dominant reduced-eye phenotypes that are sensitive to variation in genetic background. The difference in eye size between males and females is similar to that seen in wild type.
Heterozygotes have a nick near the anterior midline of the eye and the overall size of the eye is reduced.
Heterozygous L1 eyes slightly smaller with nick in anterior edge and lower half of eye reduced more than upper; overlaps wild type. Homozygous L1 eyes much smaller and less variable.