Molecular Anatomy of the Bird Cochlea

In contrast to mammals, birds recover naturally from deafness, which makes them an ideal model for inner ear regeneration research.  Here, we present a validated single-cell RNA-seq resource of the avian cochlea.  We found specific markers for three distinct types of sensory hair cells including a previously unknown subgroup, which we named superior tall hair cells.  We identified novel markers for the supporting cells associated with tall hair cells, which represent the facultative stem cells of the avian inner ear. Likewise, we present markers for supporting cells that regenerate the short cochlear hair cells. We further inferred spatial expression gradients of hair cell genes along the tonotopic axis of the cochlea.  This resource is useful for neurobiology, comparative biology, and for regenerative medicine because it provides a basis for comparative studies with non-regenerating mammalian cochleae, and for longitudinal studies of the regenerating avian cochlea.