Two other intercalating dyes are acriflavine and acridine orange. Radiolabel in the form of 32P can be inserted into nucleic acids. Internal labeling inserts 32P throughout the molecule by performing DNA replication in the presence of a 32P-labeled substrate. At least one of the dNTPs is labeled with 32P in the alpha position, which will be donated to the nucleic acid during DNA replication. End labeling is performed using polynucleotide kinase.
Autoradiography involves the exposure of photographic film by a radioactive source.
Geiger counters monitors the ionization of gases when radioactive particles interact with them. Scintillation counting measures the light emission of molecules that fluoresce upon interaction with radioactive material. This last method allows for accurate quantitation of radioactivity. Ethidium bromide is used to detect the nucleic acids. The pore size of the matrix depends on the concentration of gel materials and the degree of crosslinking.