Based on work from the 1940's before molecular tools were available, the neural crest was thought to form by interactions between neural and non-neural cell layers. "We show in this work that neural crest stem cell precursors are designated very early in development -- as early as the gastrula stages -- and in an independent fashion from those other tissues," said Martn Garca-Castro.
The researchers grew grafts of cells from "stage 3" chick embryos, before the neural plate formed, in non-inducing cultures. Surprisingly, restricted regions of the embryo generated both migrating neural crest cells and their derivative cell types, without any interaction with neural or mesodermal tissues.
"Our results are contrary to current text-book models and suggest that different modes of neural crest induction operate during development," said Martn Garca-Castro. "Interestingly, the one we have uncovered is related to the early, cranial neural crest cells, the only ones in higher vertebrates that retain bone and cartilage forming potential."