Embryos derived from homozygous females are strongly dorsalised. Homozygous adults show reduced viability, the lethal phase being between the second and third larval instar stages. Transheterozygotes with wblRP, wblM88, wblM46, wblE4 or wblAR51 also have reduced viability, and embryos derived from these transheterozygous females are dorsalised and fail to hatch.
Embryos transplanted with perivitelline fluid from Tl2 embryos exhibit a polar gastrulation. At the end of embryogenesis an almost complete restoration of pattern along the dorsoventral axis is seen. The point of injection determines the ventralmost point of the restored pattern.