%0 Journal Article %A ZUBRZYCKI, L. %A LEVINSON, SUSAN U. %T Genetic Heterology between Escherichia colik 12 and a Smooth Strain of E. coli %D 1969 %J Microbiology, %V 57 %N 1 %P 115-123 %@ 1465-2080 %R https://doi.org/10.1099/00221287-57-1-115 %I Microbiology Society, %X SUMMARY cf 2004-6, a recipient strain, and 04m2, an Hfr donor strain of Escherichia coli 04:K(undetermined): H5, were used in mating experiments with E. coli k 12. 04m2 behaved like the k 12 donor strain in mating experiments. These donor strains genetically recombined with the k 12 recipient at higher frequencies than with cf 2004–6. The results of interrupted mating experiments were also more typical with the k 12 recipient than with cf 2004–6 in that there were sharp entry times for the markers studied and linear increases of recombinants with time. The possibility that host-controlled restriction decreased genetic recombination between E. coli k 12 and cf 2004–6 was pursued. We obtained no evidence for this possibility. Instead the data suggest that genetic heterology between these strains is affecting recombination. Genetic heterology also explains why 04m2 behaves more like a k 12 donor in mating experiments with cf 2004–6. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-57-1-115