Description
Precise frequency discrimination is a hallmark of auditory function in birds and mammals. In the cochlea, tuning and spectral separation result from longitudinal differences in basilar membrane stiffness and numerous individual gradiations in sensory hair cell phenotypes, but it is unknown what patterns those phenotypes. Hypothesizing that morphogen levels might differ along the longitudinal axis of the developing cochlea, we sequenced the transcriptomes of the proximal, middle, and distal thirds of the chicken cochlea at E6.5, when postmitotic hair cells first form. Overall design: Embryonic day 6.5 chicken cochlea were dissected. Three samples were collected from each cochlear duct by cutting the duct into three approximately equal sized pieces to produce proximal, middle, and distal pieces. Each sample contained a portion of the future tegmentum vasculosum and the basilar papilla sensory epithelium. The distal piece also contained the region fo the future lagena.