title: DNA nicking favors PCR recombination.
abstract: We attempted to use the polymerase chain reaction (PCR) to monitor in vitro recombination in a plasmid containing directly repeated sequences. Some of the plasmid preparations which had not been exposed to recombination conditions were however found to behave in the PCR test as if they had undergone homologous recombination. We show here that such false positives are attributable to a small degree of nicking and/or breaking of the DNA template. Presumably, such damage allows the formation of hybrid parental duplexes containing at least one truncated strand, the 3' end of which maps within the homology; extension of this 3' end by the polymerase then results in a linkage of sequences identical to that arising from homologous recombination.
authors.affiliation: Départment de Microbiologie, Faculté de Médecine, Université de Sherbrooke, Québec, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Marton
authors.forename: L
authors.initials: L
authors.lastname: Delbecchi
authors.forename: P
authors.initials: P
authors.lastname: Bourgaux
mesh_terms: D001483:Base Sequence; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic; D012091:Repetitive Sequences, Nucleic Acid
chemical_list: D009838:Oligodeoxyribonucleotides