Lysogenization by phage P22 carrying amber mutations in Genes 12 and 18

Temperature-sensitive mutants in genes 12 and 18 of phage P22 show recessive DNA-negative phenotypes, but dominant integration-negative phenotypes. In contrast, am mutants in genes 12 and 18 are recessive for both DNA synthesis and lysogeny. The data are interpreted to indicate that the active forms of these two gene products are multimers.