Details are described here for using a rotating gel to perform pulsed field agarose gel electrophoresis (PFGE) with programmable control of the following variables: magnitude of the electrical field, polarity of the electrical field, temperature of the gel and position of the rotating disk upon which the agarose gel rests. By use of this procedure for programmable control, modes of PFGE have been explored that have the following characteristics: (i) resolution by DNA length is completely lost for DNA shorter than a critical length that increases as the pulse times increase, and (ii) resolution by DNA length is enhanced for longer DNAs that are shorter than a second critical length. This window of resolution can be moved to the position of the 2-6 Mb chromosomes of Schizosaccharomyces pombe.