Homozygous clones in the labium result in a reduction of pseudotracheal rows.
Ectopic expression of Scr results in transformation of arista to tarsus.
No gross abnormalities in brain patterning are seen in homozygous embryos. Longitudinal pathways and commissural pathways are present and appear normal. The maxillary organs of the peripheral nervous system are duplicated.
Homozygous embryos show homeotic transformation of segments T1 to T2 and labium to maxilla. Heterozygous males have fewer sex combs than wild-type flies.
Homozygous embryos show a partial transformation of prothorax to mesothorax. The labium is absent, and a second pair of maxillary sense organs lies between the normal mouthparts and prothorax. The mesothorax, metathorax and abdominal segments appear normal. Homozygous escunspecified embryos (derived from homozygous escunspecified mothers) that lack Scr+ are identical to homozygous escunspecified embryos (derived from homozygous escunspecified mothers) except that the labial pits are absent and are replaced by a second pair of maxillary sense organs, and the small tuft of ventral hairs associated with the labial pits are enlarged to form a square band of three to five rows of hairs. Antpunspecified Scrunspecified embryos have bilaterally symmetric regions of sclerotised cuticle in the prothorax.