ptc¹³/ptc^tuf-1 have enlarged eyes. The head vertex in these flies is of normal size, but all have outgrowths of head cuticle plus large numbers of missing, misplaced or ectopic head bristles. ptc^559.1/ptc^S2 flies have normal sized eyes and head vertex and a low incidence of ectopic or misplaced head bristles. They also have enlarged ocelli that are closer together than in wild-type. The zone of cell cycle arrest corresponding to the morphogenetic furrow (MF) is not significantly increased in late 3rd instar ptc¹³/ptc^tuf-1 or eye discs compared to wild-type. However, its width is uneven along the length of the furrow, being particularly narrow at the equator and wider along the margins. The distribution of dividing cells either side of the MF is disorganized: dividing cells anterior and posterior to the furrow are closer together near the equator of the disc than at the poles. Compared with wild type, there is an approximately 2 fold increase in cell division ahead of the furrow in the mutants ptc¹³/ptc^tuf-1 mutant discs show increased cell death despite the resulting enlarged eye although it is not as extensive as in ptc¹⁶/ptc^tuf-1. Occasionally a vast amount of cell death is seen in the antennal disc of ptc¹³/ptc^tuf-1 animals..

Mutants transheterozygous for ptc^tuf-1 and ptc¹³ show normal separation of wing veins L3 and L4, but display dramatic shape changes and abnormalities in the anterior margin. The wing becomes almost circular and the triple row bristles are replaced by double row bristles.

homozygous lethal