A temperate bacteriophage that infects Salmonella. The prophage inserts at a specific site on the host chromosome (between pro A and pro C). Insertion is catalyzed by an integrase (q.v.) specified by the phage. Transduction (q.v.) was discovered in Salmonella typhimurium that carried the P22 prophage. See Chronology, 1952, Zinder and Lederberg.
Subjects: Genetics and Genomics.