ZEBRAFISH PIGMENTATION MUTATIONS AND THE PROCESSES OF NEURAL CREST DEVELOPMENT

Neural crest development involves cell-fate specification, proliferati on, patterned cell migration, survival and differentiation, Zebrafish neural crest derivatives include three distinct chromatophores, which are well-suited to genetic analysis of their development, As part of a large-scale mutagenesis screen for embryonic/early larval mutations, we have isolated 285 mutations affecting all aspects of zebrafish larv al pigmentation, By complementation analysis, we define 94 genes, We s how here that comparison of their phenotypes permits classification of these mutations according to the types of defects they cause, and the se suggest which process of neural crest development is probably affec ted, Mutations in eight genes affect the number of chromatophores: the se include strong candidates for genes necessary for the processes of pigment cell specification and proliferation, Mutations in five genes remove part of the wild-type pigment pattern, and suggest a role in la rval pigment pattern formation, Mutations in five genes show ectopic c hromatophores in distinct sites, and may have implications for chromat ophore patterning and proliferation, 76 genes affect pigment or morpho logy of one or more chromatophore types: these mutations include stron g candidates for genes important in various aspects of chromatophore d ifferentiation and survival, In combination with the embryological adv antages of zebrafish, these mutations should permit cellular and molec ular dissection of many aspects of neural crest development.