In agarose gel electrophoresis, DNA and RNA are separated on the basis of size by migrating the DNA through an electrically charged agarose gel. Proteins are separated on the basis of size by using a SDS-PAGE (Sodium Dodecyl Sulfate-PolyAcrylamide Gel Electrophoresis, or on the basis of size and their electric charges via 2D (2 Dimensional) gel electrophoresis. The DNA, RNA and protein macromolecules are detected by a specific probe (e.g. a sequence specific nucleic acid probe for DNA or RNA sequences or a specific antibody probe for a protein encoded antigen) after blotting the molecules onto an appropriate membrane support.