NB6-4a-to-NB6-4t neuroblast homeotic transformations occur in Abd-Bunspecified mutants.
Homozygous clones transform posterior abdominal segments into more anterior ones, but are normal in the analia. In the genitalia, patches of cuticle bearing trichomes and bristles are often seen. Occasionally bracted bristles or a claw are seen, indicating transformation to leg tissue. Using the Minute method, more extensive transformation of genitalia into leg are seen, including leg elements such as claws, tarsus and tibia. In one case, leg structures typical of mesothoracic leg (apical bristle) has been seen in the transformed genitalia. In females, the ectopic legs substitute for much of the vulva and part of the vaginal plates, with some vaginal teeth frequently remaining. In males, the legs substitute for the hypandrium, penis apparatus and part of the clasper. Occasionally transformation of genitalia into distal antennae (2nd and/or 3rd antennal segment and arista) are seen. The transformations into leg or antenna are cell autonomous.
Many germ cells are able to coalesce along with gonadal mesoderm to form a gonad; however, some germ cells are excluded from this gonad, presumably due to the reduction in number of somatic gonadal precursors (SGPs). These 'lost' germ cells remain in an area ventral and posterior to the gonad until after coalescence.
Scrunspecified, Antpunspecified, Ubxunspecified, abd-Aunspecified mutants are profoundly affected in their development with abnormal or twisted dorsal closure.
3 mutants are isolated.