title: Positional information and pattern formation.
mesh_terms: D000818:Animals; D001693:Biological Transport, Active; D002449:Cell Aggregation; D002454:Cell Differentiation; D002455:Cell Division; D002465:Cell Movement; D004058:Diffusion; D004330:Drosophila; D006128:Growth; D006829:Hydra; D007313:Insecta; D007365:Intercellular Junctions; D008954:Models, Biological; D009024:Morphogenesis; D009030:Mosaicism; D009154:Mutation; D010944:Plants; D012038:Regeneration; D012617:Sea Urchins; D014562:Caudata; D014981:Xenopus