A technique that entails immobilisation of proteins or nucleic acids on a solid membrane support, and then detection using a specific antibody or probe of complementary nucleic acid sequence, blotting significantly increases the potential for identification and characterisation of proteins and nucleic acids. Upon transfer to a membrane, support proteins and nucleic acids become far more accessible to detection by antibodies and probes than they would otherwise be within a gel. Size-fractionation by gel electrophoresis followed by blotting is an excellent way to identify specific molecules within a mixed population of nucleic or protein molecules, and these techniques are often used in tandem.