robo12/+ mutant flies exhibit temperature-induced mobility defects.
robo1/robo2 embryos exhibit gonad compaction defects and germ cell ensheathment defects.
robo1/robo2 mutants exhibit an ectopic midline innervation phenotype (with 100% penetrance for MN-LL1 and 89% penetrance for MN-DA3).
In robo2 embryos, the pCC axon rarely aberrantly crosses the midline.
As well as the interneurons, RP2 (normally an ipsilaterally projecting neuron) can project contralaterally. RP2 and pCC can bifurcate into ipsilateral and contralateral branches. RP2 can be misrouted posteriorly. Time lapse photography shows filopodia projecting across the midline for longer than in wild type. Longer filopodia are not restricted to pathway directions. These filopodia can lead to branched growth cones. Filopodial number is not affected. Heterozygotes show a filopodial length distribution that is intermediate between wild type and homozygous mutants.
Mutant phenotype of lateral chordotonal axons includes: shorter axons or defasciculated axons.
"Fuzzy commisure" phenotype in embryonic central nervous system.