Molecular homology of F-merogenote DNA

Chromosome transfer between Escherichia coli HFR strains and Proteus mirabilis.

“…Similar findings in hybrids between E. coli and Salmonella have been interpreted as an expression of poor molecular homology.2' Preliminary experiments backcrossing WR 13 with WR 2001 and WR 2002 for other characters suggest that this hybrid acts as a better recipient than the original strain, WR 11. Similar results reported for backcrosses of Salmonella hybrids'3 23 have been explained in two ways. The fortuitous isolation of a high-frequency recipient mutant of S. typhimurium without prior mating experience'2 suggested that the low frequency of hybrid recovery in E. coli X S. typhimurium matings represented the selection of rare competent mutants from otherwise sterile populations.…”

“…23 The lack of homology between these strains is indicated by the diploid state, i.e., inefficient pairings in the lac regions without (or at least not detected) integration of the genes. Similar findings in hybrids between E. coli and Salmonella have been interpreted as an expression of poor molecular homology.2' Preliminary experiments backcrossing WR 13 with WR 2001 and WR 2002 for other characters suggest that this hybrid acts as a better recipient than the original strain, WR 11.…”

Bacterial Conjugation and Extrachromosomal Elements

“…The DNA of the F-merogenote F-Iac+ has been isolated from Proteus intergeneric hybrids and directly hybridized to the DNA of Hfr and F strains of E. coli K-12 (127). This study indicates that F-lac+ and wildtype F are equivalent to 2.5 per cent and 1.9 per cent respectively, of the E. coli chromosome.…”

The Fortunate Professor

“…In 1965 we characterized F-factor DNA (9), and a year later we published a broad study of the molecular nature of R factors (10). From 1965 to 1967, I collaborated with a number of different investigators at WRAIR, NIH, and Carnegie.…”