Abstract
Drosophila polyhomeotic (ph) is one of the important polycomb group genes that is linked to human cancer. In the mosaic eye imaginal discs, while ph(del), a null allele, causes only non-autonomous overgrowth, ph(505), a hypomorphic allele, causes both autonomous and non-autonomous overgrowth. These allele-specific phenotypes stem from the different sensitivities of ph mutant cells to the Upd homologs that they secrete.
