Neural Crest Contributions to the Development of the Vertebrate Head

Abstract

The neural crest is a major source of mesenchyme in the head, but not the body, of the vertebrate embryo. For some of these mesenchymal derivatives, the differences between the normal fates of cranial and trunk neural crest cells are not necessarily due to differences in the potentials of the cells for the various derivatives, but reflect a lack of interaction with appropriate inductive tissues. Chondrogenic potential, however, is restricted to those axial levels which normally give rise to cartilage. This chondrogenic subpopulation is not homogeneous, even prior to neural crest cell migration, cells from different axial levels display differences in migratory and morphogenetic abilities. While the events which give rise to these segregations have never been examined, some models have been proposed for the establishment of the neural crest itself.