title: Morphagen gradients. Introduction.
authors.affiliation: Department of Anatomy and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, UK.
authors.forename: L
authors.initials: L
authors.lastname: Dale
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000235:genetics; D002454:Cell Differentiation / Q000502:physiology; D004330:Drosophila / Q000196:embryology*; D004625:Embryo, Nonmammalian / Q000196:embryology; D004627:Embryonic Induction; D009024:Morphogenesis / Q000502:physiology; D015398:Signal Transduction; D014982:Xenopus laevis / Q000196:embryology*