NBs express a series temporal TFs, represented here by different colored circles. The blue outlines indicate TFs that may be shared throughout the lineage. NBs divide asymmetrically to eventually give rise to post-mitotic neurons that have both unique mTF codes, which specify individual dendritic and axonal morphologies, and terminal selector TF codes, which specify other terminal characteristics such as choice of neurotransmitter. Once differentiated, terminal selector TFs maintain the characteristics of terminally differentiated neurons.