Fig. 5. Anteroposterior patterning of the somite and primary motoneuron patterning are unaffected in obd mutants. In situ hybridization of wild-type zebrafish with probes for fgf8 or deltaD demonstrates a segmental expression pattern in the anterior somite. The expression pattern in obd homozygous mutant animals is identical to that in wild type. Antibody staining with znp-1 marks primary motoneurons in zebrafish. The pattern is identical in obd and wild-type embryos.