DNA blot (Southern)

The DNA blot or Southern blot is a molecular biology method to probe the genome for the location of a DNA sequence. Genomic DNA is first digested using a restriction endonuclease. Fragments are then separated by size using agarose gel electrophoresis. After size separation DNA pieces are blotted onto a membrane and then hybridised with a labelled nucleic acid probe. The location of the probe on the membrane is visualised either by radioactivity or antibody labelling.