Abstract
A mutant of E. coli K-12 isolated for temperature-sensitive growth harbored an alteration in ribosomal protein L9. Because the chromosomal location of the structural gene for this protein (rplI) was not known, the mutation was mapped by using various Hfr strains. The fine mapping of this gene by P1kc phage-mediated transductions revealed that it forms a gene cluster at 94 min on the E. coli genetic map together with the genes coding for 2 other ribosomal proteins, S5 (rpsF) and S18 (rpsR). The region of the E. coli genetic map containing this cluster was shorter than previously estimated by approximately 2 min.