Large hthB2 mutant clones generated in a Minute background result in ectopic ventral photoreceptor differentiation but do not cause outgrowths.
Ommatidia located in homozygous clones that are touching the dorsal rim area (DRA) of the eye lose the enlarged inner photoreceptor rhabdomeres that are typical of DRA ommatidia.
Mutant embryos show a relatively mild phenotype in the PNS, which consists mainly of dorsal localisation of LCh5 neurons in some of the abdominal segments.
Somatic clones in the head, induced during larval stages, lead to ectopic eye structures in the head. the ventral head region (gena and rostral membrane) is reduced as a consequence of the production of ectopic eyes, and the maxillary palps are frequently absent or abnormal in these clones. Occasionally incomplete ommatidia with missing photoreceptors and fewer bristles are seen, most of the times at the interface between clonal and wild-type tissue. Clones within the eye also show ommatidial polarity defects - the induction of ectopic equators is seen occurring parallel to the endogenous equatorial axis and accompanied by frequent inversion of ommatidia polarity along the anterior posterior axis. These defects are both cell- and non-cell-autonomous.
The normal pattern of the cuticle is disrupted in homozygous embryos and hthB2/Df(3R)hth embryos, with hthB2/Df(3R)hth embryos having a stronger phenotype than homozygous embryos.