A Dual Embryonic Origin for Vertebrate Mechanoreceptors

Neuromasts, the mechanoreceptors of the lateral line system of fishes and aquatic amphibians, have previously been thought to develop exclusively from embryonic epidermal placodes. Use of fate mapping techniques shows that neuromasts of the head and body of zebrafish, Siamese fighting fish, and Xenopus are also derived from neural crest. Neural crest migrates away from the neural tube in developing vertebrates to form much of the peripheral nervous system, pigment cells, and skeletal elements of the head. The data presented here demonstrate that neuromasts are derived from both neural crest and epidermal placodes.