Mapping of the Pneumococcus Chromosome. Linkage between the Genes Conferring Resistances to Erythromycin and Tetracycline and Its Implication to the Replication of the Chromosome Butler, L. O. and Nicholas, G.,, 79, 31-44 (1973), doi = https://doi.org/10.1099/00221287-79-1-31, publicationName = Microbiology Society, issn = 1350-0872, abstract= SUMMARY: In the process of constructing a map of the pneumococcus chromosome by transformation, a search for linkage groups involving the markers ery-r2, str-r41, amiA-r1, opt-r2 and tet-A has been carried out. No linkage was found amongst the first four markers, but linkage was found between ery-r2 and tet-A. The discrepancy between these results and the previously reported linkage between the loci conferring resistance to erythromycin and streptomycin is discussed. The anomalous position of the ery-r2–tet-A linkage in relation to the chromosome map obtained by the density-shift method, and the implications to the mode of replication of the chromosome, are discussed. Two models are proposed for the replication of the pneumococcal chromosome., language=, type=