Unlike in wild type, whose dendrites cluster around the photoreceptor axons in their cognate column, babo⁵² mutant Tm20 neuron clones extend their neurons laterally in medulla layer M3a and invade neighboring columns. Furthermore, the mutant dendritic branches in the internal medulla M8 layer exhibit a similar overextension phenotype. The mutant Tm20s' axons are correctly targeted to the fifth layer of the lobula.

The transverse nerve makes ectopic connections at the neuromuscular junction in babo³²/babo⁵² larvae.

Ectopic connections are formed at the neuromuscular junction in babo³²/babo⁵² larvae.

Single cell babo⁵² clones in mushroom bodies have overextended axons with hardly any axon breaks throughout the entire neurite.

babo³²/babo⁵² animals pupariate in the food, show defects in anterior spiracle eversion (43%) and a significant incidence of bent legs at pharate stages (64%).

babo³²/babo⁵² prepupae have a smaller brain lobe than normal and a reduced lamina plexus. Axon projections of the R7/R8 photoreceptor cells to the medulla are abnormal, with their growth cones forming bundles instead of the normal regular lattice network seen in controls. Photoreceptor axon targeting is still highly perturbed in 3 day old pupae and rotation of the medulla and lamina relative to one another does not take place. In the most strongly affected cases, babo³²/babo⁵² mutants show a great reduction in the number of lamina cap and cartridge neurons. babo³²/babo⁵² third instar larvae have a disorganised and smaller medulla neuropil compared to wild type. The number of glial cells at both the lamina and medulla is reduced in babo³²/babo⁵² white prepupae compared to wild type.

Homozygous mutant photoreceptor clones induced in the eye disc show normal axon projections to a heterozygous brain lobe.

The optic lobe is much smaller than wild type in babo³²/babo⁵² white prepupae. There is an approximately 50% decrease in the number of medial optic lobe neuroblasts compared to controls, a decrease in the number of ganglion mother cells produced from these medulla neuroblasts and a subsequent decrease in the number of maturing neurons within the medulla cortex. There is also a decrease in the number of lamina precursor cells and thus a decrease in the number of lamina cartridges and laminar neurons.

The number of cells in M phase in the developing optic lobes is significantly reduced in babo³²/babo⁵² third instar larvae compared to controls. The size of the outer proliferation center and inner proliferation center zones is reduced in these larvae, although they still contain many cells in S phase. The ratio of M-phase cells to S-phase cells is thus reduced in the mutant optic lobes compared to wild type.

R7 photoreceptor clones homozygous for babo⁹ invade neighboring columns occupied by wild-type R7s.

Embryos derived from babo⁵² germline clones crossed to babo³² fathers show a greater penetrance of ISNb and SNa axon guidance defects compared to zygotic mutants.

Stage 17 babo⁵² embryos derived from babo⁵² germline clones show axon guidance defects, such as misrouting of the SNa and SNb.

Photoreceptor R1-R6 axons project into the brain and form a relatively normal but very reduced lamina in babo³²/babo⁵² mutant larvae, but R7 and R8 axons never form a normal lattice network and their growth cones are collapsed. The medulla neuropil is significantly reduced in size and altered in morphology in babo³²/babo⁵² mutant larvae.

When single cell mutant clones in adult γ neurons, larval projections persist until adulthood in about half of these neurons.

Homozygous larvae show slowed development and enlarged anal pads. Very few homozygotes progress to the pharate stage. Larvae do not leave food and do not evert their anterior spiracles. Adult structures of a babo⁵²/babo³²mutant derived from germ line clones are reduced in size. Embryos derived from mutant germ line clones show a normally patterned, four chambered midgut. Homozygous clones of adult tissue (wing and leg) show no mutant phenotype.

babo³²/babo⁵² has axon & eye photoreceptor cell phenotype, suppressible by CycA^C8LR1/CycA[+]

babo³²/babo⁵² has lamina phenotype, suppressible by CycA^C8LR1/CycA[+]