A process of interaction during development by which one part of the embryo (such as a specific tissue or cell type) causes another part to differentiate. It can be positive or instructive (specification of a developmental fate) or negative (restriction of developmental potential). Primary and secondary inductions take place early and later in development, respectively. It was Hans Spemann ((1869-1941) who first identified primary induction, which he considered to be the alteration of cell fate as a consequence of interaction with neighbouring cells.
See Apical ectodermal ridge (AER), Archenteron, Blastopore, Bone Morphogenetic Proteins (BMPs), Chordin, Competence (embryology), Critical period, Determination, Epigenetic emergence, Experimental embryology, Hensen’s node, Mesoderm, Morphogenetic field, Noggin, Organizer, Permissive interaction, Sensitive period