At permissive temperature (17^oC) flies hemizygous for E(z)¹²) survive until the pharate adult/adult stage, have wild type sized imaginal discs and have a weak E(z) phenotype. At the restrictive temperature (27^oC) larval hemizygotes resemble amorphic E(z)⁵ mutants. When shifted prior to the beginning of the third larval instar, E(z)⁵ mutants have small discs and die just after puparium formation, larvae shifted after this time have wild-type sized discs and die later in pupal development.

Homozygotes exposed to 27^oC for 8 hours during the third larval instar stage can develop transformations of the second and third legs to first legs. Homozygous females are sterile and do not produce any eggs even when maintained continuously at a permissive temperature. Ovaries from homozygous females maintained at 29^oC for 4 days contain a normal number of ovarioles and apparently normal stage egg chambers up to stage 3 or 4. However, there is degeneration of the nurse cells and little growth in size of egg chambers beyond the earliest stages.

Mutants form puparia.

Dominant suppressor of z mutants.