The neural crest provides a useful model to learn how cell fate diversification is regulated during vertebrate development. Our approach is to isolate zebrafish mutations in which the development of neural crest derivatives is disrupted, in order to learn about the underlying genetic mechanisms. We describe a screen in which parthenogenetic diploid embryos are examined both for visible phenotypes and for cellular defects in neural crest-derived sensory neurons recognized immunohistochemically. We present preliminary results from this screen and briefly describe a few representative mutations. We also discuss the general utility of our strategy and comment on the future directions of this approach.