What is discontinuous gel electrophoresis?

Discontinuous gel electrophoresis is a type of gel electrophoresis technique in which the gel is divided into two discontinuous parts. The large pore, non-restrictive gel called the stacking gel is layered on top of the smaller-pore separating gel. The two sections are different in terms of their polyacrylamide concentrations. The restrictive gel, which has a lower concentration of polyacrylamide, is stacked on top of the separating gel, which has a higher polyacrylamide concentration. Discontinuous gel electrophoresis provides a much higher resolution than that obtainable in a continuous assay.