Correlation between map position and phenotype of CTI mutants in the c cistron of Rhizobium meliloti phage 16-3.

Nine temperature-sensitive clear mutations (Cti) in the C cistron (coding for the repressor protein) of Rhizobium meliloti temperate phage 16-3 were characterized according to the inductive temperature, the immunity of cells lysogenic for these mutant phages to superinfection by homoimmune weak virulent mutants, the phenotype of double-ti mutants and interallelic complementation. The results indicate that mutations of similar phenotypic expression are clustered on the genetic map. Furthermore, it seems probable that the C cistron of the original phage 16-3 is identical to that of the independently isolated phage strain 36.