Fig. 8. Schematic depicting genetic relationships between Barhl2 and other transcription factors involved in the development of amacrine cells. Retinal progenitors may acquire the competence to produce amacrine cells by the activation of an unknown factor(s). Competent progenitor cells are then specified by Math3 and Neurod1 to become amacrine cells. Some of the newly generated amacrine cells may differentiate into glycinergic cells by the action of Barhl2 and Pax6. Alternatively, Math3 and Neurod1 may also be able to specify Pax6⁺ progenitors into amacrine cells (broken arrow). It is known that Pax6⁺ progenitor cells have the potential to differentiate into rod, cone, horizontal, bipolar, ganglion and Müller cells.