Balancing cell numbers during organogenesis: Six1a differentially affects neurons and sensory hair cells in the inner ear

► Six1a function balances the number of hair cells and neurons in the inner ear. ► Six1a acts as a transcriptional repressor in the neuronal lineage. ► Six1a acts as a transcriptional activator in the sensory hair cell lineage. ► Six1a function in the neuronal lineage likely involves chromatin remodeling.