No effect on the faf eye phenotype.

Homozygous mutant females crossed to mutant males produce lethal embryos showing hypertrophy of the central nervous system at the expense of the epidermis, a small patch of dorsal cuticle remaining but no ventral cuticle. This embryonic phenotype (as well as the reduced eye phenotype of viable pcx adults) resembles that of amx.

Homozygous early gastrula embryos derived from homozygous females give rise to a greater than wild-type number of neurons in culture.

Homozygous pcx lethal embryos can be partially rescued almost up to hatching by preblastoderm microinjection of wild-type or amx ooplasm.

Germ line clonal analysis demonstrates the germ-line dependency of the pcx embryonic lethal phenotype.

Homozygous pcx lethal embryos can be rescued genetically; some mutant females (but not pcx¹ homozygotes) crossed to wild-type males produce viable adult pcx/+ female offspring the pcx/Y male offspring are lethal. pcx/+ heterozygous females, which are fertile, crossed to viable pcx/Y males (also fertile) produce viable adult males (pcx/Y and +/Y) and viable adult females (pcx/pcx and pcx/+).