has soma location directly develops from Usib neuron A1-7 DO2sib neuron VFB:FBbt_00001571 Sibling neuron to the A1-7 DO2 motor neuron developing from the third ganglion mother cell that differentiates from neuroblast NB7-1 in abdominal segments. U3sib neuron fly_anatomy.ontology FBbt:00001571 Usib neuron abdominal neuron ganglion mother cell GMC7-1c larval abdominal segment A1-7 ventral ectoderm derivative larval CNS neuron