Transheterozygotes are semi-lethal (very few escapers), exhibit severe cuticular defects in adults, premeiotic defects and a mutant brain phenotype. Abnormalities in premeiotic growing stage cysts; nuclear diameters are larger or smaller than expected, meiotic spindles are abnormal. Postmeiotic onion stage cysts are also abnormal with large variation in nuclear sizes reflecting both mitotic and meiotic nondisjunction. Male transheterozygotes die before maturing and have no motile sperm in testes.