Two-Dimensional Agarose-Gel Electrophoresis of DNA Topoisomers

Gel electrophoresis in one dimension is often insufficient to distinguish various molecular species of DNA, since different conformers, and sometimes DNA molecules of totally different structures may have the same electrophoretic mobility. These DNA species can be resolved by two-dimensional (2-D) gel electrophoresis, which involves two successive operations carried out with one gel slab under different conditions and in orthogonal directions.