Practice question

Vertebrate neural crest cells display exceptional migratory plasticity and conditional fate determination. Cranial crest normally contributes to facial skeleton, but when transplanted heterotopically into trunk pathway, these cells abandon craniofacial program and differentiate into melanocytes, dorsal root ganglia and sympathetic neurons appropriate to new axial level. Fate reprogramming occurs because crest cells interpret local environmental cues including BMP, Wnt, endothelin 3 and retinoic acid encountered along migration routes and at target sites, which modulate transcription factors Sox10, FoxD3 and Mitf. Therefore, environment rather than origin dictates final differentiation.