It is widely accepted that the inner ear labyrinth and the neurons of the cochleovestibular ganglion (CVG), which innervates the inner ear’s sensory epithelia, derive entirely from the otic placode, an ectodermal region that invaginates during embryogenesis to form the otic vesicle (OV) and the CVG. Here (p. 5403), by genetically labelling cranial neuroepithelial cell (NEC) lineages, including neural crest cells, in mice, Bernice Morrow and colleagues show that cells from the neural tube invade the otic epithelium in vivo and that NEC descendants constitute a significant proportion of the OV. NEC descendants, they report, are localised within the sensory epithelia of the saccule and utricle (the inner ear structures that are sensitive to movement) and the cochlea (the auditory portion of the inner ear) throughout development and into adulthood, and differentiate into neurons, hair cells and supporting cells. By revealing the inner ear’s dual embryonic origin, these results challenge the current model for the neurosensory development of the inner ear.

© 2011.