title: Existence of two types of integrations.
authors.forename: F
authors.initials: F
authors.lastname: Wurm
authors.forename: R
authors.initials: R
authors.lastname: Arathoon
mesh_terms: D000818:Animals; D005784:Gene Amplification / Q000187:drug effects; D008727:Methotrexate / Q000494:pharmacology; D009154:Mutation; D015202:Protein Engineering
chemical_list: D008727:Methotrexate