Somatosensory mechanisms in zebrafish lacking dorsal root ganglia.

Dorsal root ganglion (DRG) sensory neurons transmit all somatosensory information from the trunk region of the body. erbb3 mutant zebrafish do not form DRG neurons because the neural crest cells that generate them migrate aberrantly. Here we report that homozygous erbb3 mutants appear to swim and feed normally, and that they survive through adulthood, despite never forming DRG neurons. The source of sensory compensation in adult erbb3 mutants remains unknown, although it may be from lateral line ganglion neuromasts which are reduced, but present, in erbb3 mutants. We also provide new information about the development of DRG neurons in wild-type juvenile zebrafish.