 Neural mesenchyme soon undergoes a mesenchymal–epithelial transition under the influence of WNT6 produced by ectoderm to form somites.These structures will undergo a secondary EMT as the somite tissue migrates later in development to form structural connective tissue such as cartilage and skeletal muscle.Neural crest cells (NCCs) form from neuroectoderm, instead of the primary mesenchyme, from morphogenic signals of the neural crest.