3.3. DNA detection using southern blots with DIG labelling

Southern blotting was invented by Edward M Southern as a means for detecting specific nucleotide sequences in a complex mixture and determining the size of the restriction fragments, which are complementary to a probe. Southern blotting combines transfer of restriction-enzyme-digested and then electrophoresis-separated DNA fragments from a gel to a membrane and subsequent detection by probe hybridization. A variety of non-radioactive methods have been developed to label probes for detection of specific nucleic acids. The Roche Applied Science DIG system is a simple adaptation of enzymatic labelling and offers a non-radioactive approach for the safe and efficient labelling of probes for hybridization reactions.