Electrophoresis is a technique of separation of charged molecules under the influence of an electrical field so that they migrate in the direction of an electrode bearing the opposite charge. DNA is a negatively charged molecule, hence it moves toward the anode. Through the pores of agarose gel, DNA fragments segregate based on size. The separated DNA fragments can be seen only after staining the DNA with ethidium bromide (EtBr) followed by exposure to UV radiation as bright orange coloured bands.