Transheterozygotes are female sterile, exhibit abdominal, brain and premeiotic defects. 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 are either sterile or have very poor fertility.