It is imperative that one be able to determine the amount of DNA present in individual bands, or clusters of bands. To achieve this, the individual lanes must be separated by enough distance so that lateral diffusion of DNA during electrophoresis does not result in partial overlap of the lanes. A custom ordered comb with 6 mm wide wells separated by 6 mm spacers gives good results. This limits one to ~24 wells on a typical sequencing apparatus intended for imaging on a 14" x 17" piece of X-ray film or imaging screen (Betascope or phosphorimager type).