title: The origin of bacteriophage P221.
mesh_terms: D001434:Bacteriophage Typing; D004463:Ecology; D009588:Nitrogen Mustard Compounds / Q000494:pharmacology; D011830:Radiation Effects; D011831:Radiation Genetics; D011995:Recombination, Genetic; D012483:Salmonella Phages; D012486:Salmonella typhimurium; D014466:Ultraviolet Rays
chemical_list: D009588:Nitrogen Mustard Compounds