Single cell approaches are causing biologists to re-evaluate classical ideas of cell types and how they arise during embryonic development. One population of particular interest is the neural crest, because it migrates throughout the body to give rise to a huge variety of derivatives such as peripheral neurons, pigment cells and bones of the skull. How do such migratory cells navigate through ever-changing environments yet reliably acquire these diverse fates? Our single cell transcriptomic studies in zebrafish suggest that they do so through a series of lineage bifurcations.

Timing is crucial to the nervous system; the ability to rapidly detect and process subtle disturbances in the environment determines whether an animal can attain its next meal or successfully navigate complex, unpredictable terrain.