Deletion and rearrangement of plasmld DNA during transformation ofEscherichia coliwith linear plasmid molecules

Abstract

When E.coli was transformed with linearized pBR322 DNA, many transforinants contained recircularized plasmids bearing deletions and other rearrangements. Most aberrant molecuies were monomeric but dimeric but − bacteria with type hib deletants predominating in transformants. This indicates that exonuclease III is important for perfect recyclization of plasmids and the generation of type I deletants. In vivo recyclization of in vitro ligation products explains many of the aberrant DNA molecules that are encountered during gene cloning.