Lethality occurs in the late embryonic and first larval instar stages. The majority of hemizygotes die as larvae. A few homozygotes survive to late pupal stages and display pattern duplications, sometimes on many body segments. Mutant embryos derived from germ-line clones show an abnormal deletion-duplication phenotype in each segment, similar to that of ptc mutants. The denticle belts are composed on average of five to six denticle rows. The width of the denticle belts is also reduced. A few embryos show an anterior open phenotype.