Blotting assays

THE MODERN BLOTTING assay is based on the work of E. M. Southern, who transferred fragments of DNA to cellulose nitrate filters and then hybridized them with radioactively labeled RNA. The DNA blotting assay hence bears his name and is called the 'Southern blot'; the developers of later assays for RNA and protein whimsically followed this tradition and named the new assays the 'Northern blot' and the 'Western blot,' respectively. These assays provide a valuable means to detect the presence and condition of specific nucleic acid or protein sequences wig preparations of total DNA, RNA, and/or protein from cultured cells or tissues, including both normal and tumor tissue.