A) Southern blot hybridized with radiolabeled target DNA. A photo of the first dimension gel slice separating the mixed reaction products is positioned horizontally across the top of the blot to illustrate where the reaction products migrated. Tc: supercoiled target, To: nicked target, T* and Tr: closed, relaxed target, Tintra: intramolecular recombination product, SEJP: single-end joined product. B) Model for disintegration from SEJP. Supercoiled donor and target DNA molecules are joined to form SEJP. The free 3' OH group on the end of the target DNA attacks the Mu end, separating the SEJP into closed, relaxed target and nicked donor DNA.