2D Gel Electrophoresis of mtDNA

The neutral/neutral two-dimensional (2D) agarose gel technique has proved to be a powerful tool for analyzing DNA structure. It was initially adapted and developed by Brewer and Fangman to localize and define bidirectional DNA replication origins on plasmids in yeast (1 ). Since then, neutral/neutral 2D gels have been used to analyze chromosomal replication origins, the efficiency of replication origin use, direction of replication fork movement, and barriers to DNA replication fork progression (reviewed in ref. 2 ). In recent years, this technique has also been used to analyze rolling circle replication in T4 phage (3 ) and topologically complex forms of intact plasmid DNA (4 ).