Homozygous embryos are U-shaped.

Homozygous clones in the lateral part of the notum differentiate normally. Clones that extend into the scutellum fail to differentiate, producing large gaps in this region. Clones touching the dorsal midline are associated with a cleft in the thorax, and clones extending into the dorsocentral area are associated with a lack or mis-positioning of the dorsocentral bristles. Dorsocentral bristles produced by wild-type cells in flies with clones in part of the dorsocentral area are also misplaced from their normal positions.