Yip1d1^1-21 mutant ddaC neuron clones show severely simplified dendrite arbors with fewer dendritic termini in white pre-pupae and show strong pruning defects in pupae (16h APF).

Mutants have reduced dendritic arbors but normal axonal growth in the class IV dendritic arborization (da) neurons.

Homozygous class IV da neuron single cell clones have reduced dendritic arbors; the total dendritic length in mutant ddaC neuron clones is only 14.9% that of controls. Axonal growth appears normal in these single cell clones, apart from subtle changes at the terminals (the short fibres which resemble filopodia are often missing). The discrete Golgi structures that are normally found in the soma of these cells and the discrete Golgi outposts normally seen in the dendrites are replaced by diffuse structures (as assayed by staining with a Golgi marker).