Simple miniaturized gel system for DNA sequence analysis

A simple miniaturized gel system suitable for DNA sequencing is described. Small ultrathin polyacrylamide gels are cast, eight or more at a time, using standard microscope slides. Gels, ready to use, can be stored for ∼2 weeks. Gels are run horizontally in a standard mini-agarose gel apparatus. Typical run times are 6–8 min. A novel sample loading system permits volumes of standard sequencing reactions as small as 0.1 µl to be analyzed. Sequencing ladders were visualized using 35S-labeled DNA by autoradiography and by colorimetric detection. Band resolution compares favorably with that of large gels. The methods introduced here serve as a step toward the miniaturization of DNA sequencing and are amenable to automated sample loading and detection.