Mutant embryos have defects in germ cell migration; by stage 11, the germ cells have migrated correctly through the midgut epithelium and along the midgut towards the dorsal side of the embryo, but they are delayed in their movement from the gut to the mesoderm, so that by stage 14, although some germ cells are within the gonads, about 50% of the germ cells are at ectopic locations, either on the midgut or in the posterior end of the embryo. The embryos show a delay in the transition of the midgut from an epithelium to a mesenchyme, which has normally started by stage 11 in wild-type embryos. At stage 11, the posterior midgut is shorter than normal. The number and distribution of lateral mesoderm cells appears similar to wild type during stages 10-11. However, some mutant embryos show a reduction in the number of somatic gonadal precursor cells at later stages (when the embryonic gonad coalesces). Most mutant embryos develop into crawling larvae and can pass coloured yeast normally through their digestive systems.