Fig. 5.

Purification of gapped DNA by electrophoresis in a 1.4% agarose gel. Following electrophoresis, lanes A, C, and E are cut out and stained with ethidium bromide. These lanes should contain four major bands: gapped DNA, circular ssDNA, large dsDNA fragment, and displaced ssDNA. Other higher order bands correspond to VCS-M13 helper phage DNA (∼ 6 kb) present in the circular ssDNA preparation and also to oligomeric forms of plasmid ssDNA. Using these bands as markers, the area that contains the gapped DNA is cut out of lanes B and D (dashed red boxes), and then purified by electroelution.