The inner ear is a suitable system to study the mechanisms involved in the specification of different functional domains during morphogenesis. Using single and double in situ hybridization (ISH) we show that three transcription factors (Otx2, Gbx2and Pax2) and a member of the fibroblast growth factor family (Fgf8) could participate in the compartmentalization of the otic vesicle and in the formation of the acoustic-vestibular ganglion.