title: Theories of preformation of encasement, etc. and cellular differentiation.
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D004247:DNA / Q000502:physiology; D004622:Embryo, Mammalian / Q000502:physiology*; D004625:Embryo, Nonmammalian; D008954:Models, Biological
chemical_list: D004247:DNA