A model developed by Louis Wolpert to explain pattern specification (q.v.) during development. His idea is that each population of cells in an embryonic structure lies in a field that contains a gradient of a chemical morphogen (q.v.). The position in the field determines the concentration of morphogen, and the cells are programmed to enter one of a number of developmental pathways depending on the concentration level of the morphogen to which they are exposed. See Chronology, 1969, Wolpert.
Subjects: Genetics and Genomics.