We have cloned a homolog of Paxin the retina at later stages does not result in any 6 in Xenopus laevis. Its deduced amino acid sequence significant bias toward formation of amacrine or ganhas a 95% overall identity with Pax-6 homologs in other vertebrates. It is expressed early in developglion cells or away from photoreceptors. Ectopic exment in cells fated to form the eye and parts of the pression of the proneural gene NeuroD alters the forebrain, hindbrain, and spinal cord. It has two pattern of Pax-6, substantially reducing its expresphases of expression in the eye. In the early phase, sion in the eye field and later reducing or eliminating from stage 12.5 to stage 33/34, Xenopus Pax-6 is exthe eye itself. Our results show that Pax-6 expression pressed throughout the developing retina. In the late appears to be necessary, but not sufficient, for eye phase, after stage 33/34, it is excluded from mature formation in Xenopus. แญง 1997 John Wiley & Sons, Inc. cells in the outer half of the retina and from cells in J Neurobiol 32, 45-61, 1997. the ciliary marginal zone, remaining only in ama-Keywords: eye; homeobox; misexpression; NeuroD; crine and ganglion cells. Misexpression of Pax-6 early paired in development results in axial defects, but no specific