Alternate approach to sequencing double-stranded template DNAs.

While attempting to determine nuclear acid sequence of a gene of interest, we made the following observation. Occasionally supercoiled DNAs from plasmid minipreparations were not amenable to sequencing. We found that linearizing these DNAs resulted in functional templates. Thus we find, on those occasions where template preparations are not of high purity, sequencing from linearized plasmids is desirable and timesaving because it avoids either reisolations of fresh template DNAs or further purifications.