Homozygous clones of substantial size can be produced in the eye when the clones are induced 1-2 days after egg laying. Homozygous clones in the wing disc appear to proliferate normally. The mechanosensory bristles in homozygous wing clones are sometimes kinked. Homozygous clones in the eye produce a slightly roughened eye surface. Approximately 20% of the ommatidia within these clones are missing one or two photoreceptors. Some photoreceptors show structural defects, including disordered packing of microvilli and split or buckled rhabdomeres. The number of photoreceptors with such abnormal rhabdomeres varies from clone to clone but never exceeds 5-10%. Defects appear equally severe in small or large clones. No dramatic differences in the organisation of the rough ER or Golgi membranes is seen in homozygous (those with or without contorted rhabdomeres) or neighbouring wild-type photoreceptors. Occasionally, homozygous photoreceptors show a slight increase in the abundance of ER near the Golgi and slightly increased levels of vesicles and multivesicular bodies. No defects in the positioning of mitochondria or nuclei are seen. The defects seen appear to be cell autonomous. Degenerating photoreceptors are seen at a low frequency in flies aged for more than two weeks after eclosion. Bristles in clones in the adult epidermis may lie flat or twisted along the epidermal sheet rather than projecting outward from its surface. The deflection of individual bristles with a tungsten needle usually causes a bend or kink rather than the pivoting needed to elicit the wild-type grooming reflex. The scutellar macrochaetae are usually approximately 20% shorter than normal. This length defect is less evident in shorter macrochaetae and is not seen in microchaetae. The tips of bristles are often contorted and the contortions are most severe at the tips of long macrochaetae, which always have flattened, flared or twisted tips. Microchaetae show bluntness or a slight tip swelling. No defects are seen in the remainder of the integument, including the bristle sockets, the nonsensory hairs of the epidermal cells or the epidermal cuticle sheet. The severity of the defects are not detectably affected by clone size. The cuticle layers of homozygous scutellar bristles are quite thin. This effect is more pronounced at the tips of the bristles than at their bases.

Khc[+]/Khc²⁰ is an enhancer of paralytic | third instar larval stage | posterior | recessive phenotype of stai^B200