side^H143/Df(3R)Tl-P embryos show defects in all of the motor axon projection branches; 89% of hemisegments lack the ISNd branch, 59% lack the SNc, 90% lack the ISNb at the M6/7 muscle cleft, 75% lack the ISNb at the M13 muscle cleft, 85% lack the ISNb at the M12 muscle cleft, 9% lack the dorsal SNa branch, 13% lack the lateral SNa branch, 3% lack the first branch of the ISN, 7% lack the second branch of the ISN and 43% lack the third branch of the ISN.

Defasciculation defect, motor axons have two instead of five characteristic branches of motor projection. Motor axons remain fasciculated with pioneer axons and consequently extend further into the periphery beyond the muscle target.