Agarose is useful in separation of nucleic acids electrophoretically because agarose gels have larger pore sizes than cross linked acrylamide gels at low concentrations and in chromatographic separations by either beading the agarose or cross-linking it. Agarose gels are also used in immunoelectrophoresis (IEP) and double-diffusion Ouchterlony plates to demonstrate antibody-antigen reactions.