MUTATIONS AFFECTING CRANIOFACIAL DEVELOPMENT IN ZEBRAFISH

In a large-scale screen for mutations affecting embryogenesis in zebra fish, we identified 48 mutations in 34 genetic loci specifically affec ting craniofacial development, Mutants were analyzed for abnormalities in the cartilaginous head skeleton. Further, the expression of marker genes was studied to investigate potential abnormalities in mutant rh ombencephalon, neural crest, and pharyngeal endoderm, The results sugg est that the identified mutations affect three distinct aspects of cra niofacial development. In one group, mutations affect the overall patt ern of the craniofacial skeleton, suggesting that the genes are involv ed in the specification of these elements. Another large group of muta tions affects differentiation and morphogenesis of cartilage, and may provide insight into the genetic control of chondrogenesis, The last g roup of mutations leads to the abnormal arrangement of skeletal elemen ts and may uncover important tissue-tissue interactions underlying jaw development.