title: Genetic and physicochemical characterization of Escherichia coli strains carrying fused F' elements derived from KLF1 and F57.
abstract: Although the two F' elements, F57 (carrying his(+)) and KLF1 (carrying leu(+)), cannot normally coexist in the same cell, crosses between RecA(-) strains of Escherichia coli carrying these two elements gave rise, at a low frequency, to progeny carrying both the his(+) and leu(+) markers in an extrachromosomal state. Genetic studies showed that the his(+) and leu(+) markers were now linked, and centrifugation studies of F' DNA isolated from these strains confirmed the presence of a new species of DNA molecule of altered size. It is proposed that the his(+) and leu(+) genes in these strains are covalently linked on a single "fused" F' element.
mesh_terms: D000166:Acridines; D000483:Alleles; D002247:Carbon Isotopes; D002499:Centrifugation, Density Gradient; D002874:Chromosome Mapping; D002876:Chromosomes, Bacterial; D003090:Coliphages; D003433:Crosses, Genetic; D003470:Culture Media; D004269:DNA, Bacterial; D004279:DNA, Viral; D004926:Escherichia coli; D005111:Extrachromosomal Inheritance; D005815:Genetic Code; D008040:Genetic Linkage; D005838:Genotype; D008970:Molecular Weight; D009690:Nucleic Acid Conformation; D011995:Recombination, Genetic; D012737:Sex Factors; D014161:Transduction, Genetic
chemical_list: D000166:Acridines; D002247:Carbon Isotopes; D003470:Culture Media; D004269:DNA, Bacterial; D004279:DNA, Viral