Between 3 and 6% of eggs produced by females carrying orbNH.Hsp83.T:Ecol\lacZ have ventralised chorions. 23-45% of eggs produced by orbF343/+ females carrying one copy of orbNH.Hsp83.T:Ecol\lacZ have ventralised chorions (depending on the orbNH.Hsp83.T:Ecol\lacZ line used).
orbNH.Hsp83.T:Ecol\lacZ acts as a dominant negative allele.