Imprecise excision of the insertion in Dscam05518, resulting in a deletion of sequences in the Dscam exon 4 cluster (exons 4.3 to 4.6 are lost).
Single cell clones of mushroom body α/β neurons that are homozygous for DscamB7-2 acquire two primary axonal branches that divergently extend away from each other, as occurs in wild-type single cell α/β neuron clones.