Research in our laboratory aims to elucidate the molecular mechanisms of hair-cell development and operation and to determine how these mechanisms relate to human hearing and deafness. 36 million American adults report some degree of hearing loss, and 2 to 3 out of every 1,000 children in the United States are born deaf or hard-of-hearing. Often, loss of hair-cell function in the inner ear results in these hearing impairments. The hair cell is a mechanoreceptor that is essential not only for hearing but also for balance and for the detection of water movement by aquatic vertebrates. This receptor represents mechanical stimuli as electrical responses that are relayed to the brain. To understand the molecular basis of hearing, we have determined the hair-cell transcriptome and are interrogating it with functional genomics involving the zebrafish (Danio rerio) model system and the mouse (Mus musculus). We are predominately focused on determining the developmental and functional mechanisms of two regions of the hair cell—the mechanosensitive hair bundle and the synaptic ribbon.