lethal | recessive
Heterozygotes are normal in a wild-type background, but Gt-21/+ ; gt-31/gt-31 flies are male-sterile and have a giant phenotype. RK3.
Gt-21, gt-31 has visible | dominant phenotype
Gt-21, gt-31 has male sterile | dominant phenotype
Gt-21, gt-31 has visible | recessive phenotype