We found that numerous developmental transcription programs initiated at successive stages of postmitotic differentiation are maintained in the same clade of mature neurons (Figure 7A–G). It is possible that a hierarchy of transcription programs progressively restricts cell fate and establishes their competence in responding to subsequently initiated programs that guide the migration, differentiation and maturation of GABAergic neurons. Our results further suggest that most developmental programs persist in mature neurons and constitute a transcriptional resume that may maintain cell phenotypes and identity.
