63.7 +/- 8.3% of Nf-YC⁴⁰ photoreceptor cell R7 neurons mistarget to the M3 layer in the brain (this is the layer in which wild-type R8 cell axons terminate) in animals containing large mutant clones in the eye.

Mutant photoreceptor R8 and R1-R6 neurons target correctly to the M3 layer and the lamina respectively in eyes containing large patches of homozygous tissue.

Homozygous pharate adults have a disorganised array of R7 and R8 photoreceptor axons in the medulla and defects in the rotation of the lamina with respect to the medulla. Mutant ommatidia contain R7 rhabdomeres, as in wild type.

Approximately 75% of mutant photoreceptor R7 axons terminate in the M3 layer of the medulla (this is the layer in which wild-type R8 cell axons terminate) in animals containing large mutant clones in the eye.

Mosaic flies in which a fraction of R7 neurons are mutant show mistargeting to the M3 layer of the medulla in approximately 17% of the mutant neurons.

The targeting of mutant R7 neurons to the temporary R7 layer in the medulla at 30% after puparium formation (APF) is normal, but extension to the final target layer at 70% APF is often disrupted, with many R7 neurons terminating in the M3 layer.