A method used to separate, identify, and purify molecules of different molecular weight and/or structure. It is specifically applied to the separation of protein or DNA fragments where it is rapid, simple, and accurate, and the separated molecules can be visualized directly by staining with dyes. The electrophoretic migration rate of molecules through agarose gel is dependent on the following parameters:1.Molecular size: molecules pass through the gel at rates that are inversely proportional to the log of their molecular weight.2.Agarose concentration: a molecule of a given size migrates at different rates through gels containing different concentrations of agarose.3.Molecular conformation: a molecule of the same molecular weight but of a different conformation will migrate at different rates. Generally, closed circular or globular forms will migrate faster than linear forms.4.Electric current: at low voltages the rate of migration is proportional to the voltage, but as the voltage is increased the rate of migration of high molecular weight fragments is increased differentially.