A three-factor cross in Salmonella typhimurium was performed using bacteriopage P22. The cross between an arg-leu-his- recipient bacterium and bacteriophage P22, which was grown on an arg+leu+his+ strain. 1000 arg+ transductants were selected and tested on several selective media by replica printing. The following results were obtained: Arg+leu-his- 583 Arg+ […]