| Lateral views of a 6 day old colorless mutant (upper panel) and its phenotypically normal sibling. Black pigment is evident in the wild-type sibling, but virtually all pigment (apart from in the retina) is missing in the mutant. Defects are also present in the ear (arrow) and the peripheral nervous system (not shown). The swimbladder is also not inflated, a defect found in many embryonic lethal lines. Mutations in colorless disrupt the sox10 gene; in humans, haploinsufficiency at the SOX10 locus results in Waardenburg-Shah syndrome, characterized by pigmentation defects of the skin, hair and iris, a loss of enteric ganglia (Hirschsprung's disease) and deafness. |
