Imaginal discs of homozygous larvae are small.

Larvae have small imaginal discs.

Homozygous larvae never form puparia. Mutant larvae have smaller imaginal discs than normal (the maximum size is similar to the size of wild-type mid-third instar discs) which cannot differentiate into adult structures when injected into metamorphosing normal larvae. The eye-antenna, leg, wing, haltere and genital discs are abnormal. The discs reach their maximum size in 7 day old larvae at 25^oC and then degenerate. Late second instar mutant wing discs and eye-antenna-brain complexes injected into wild-type adult females grow substantially in in vivo culture, but are unable to differentiate into adult structures when injected into metamorphosing normal larvae. Wings discs from early third instar wild-type larvae injected into late second or early third instar mutant larvae show reduced growth compared to control wild-type discs injected into wild-type larvae. These discs can differentiate when injected into metamorphosing larvae. Homozygous clones induced early in development (until the middle of the second larval instar stage) are significantly smaller than control clones. The frequency and size of clones induced at later times is indistinguishable from controls.