Blotting is a common laboratory procedure in which biological molecules in a gel matrix are transferred onto nitrocellulose paper for further scientific analysis. The biological molecules transferred in this process are DNA fragments, RNA fragments, or proteins. Because the isolation and characterization of these types of materials is at the center of much molecular biology research, blotting is one of the most useful techniques in the molecular biology laboratory.

The blotting procedure is named differently depending on the type of the molecules being transferred. When the molecules to be transferred are DNA fragments, the procedure is called a Southern blot, named for the man who first developed it, Edward Southern, a molecular biologist at Oxford University. The Northern blotting procedure, which transfers RNA molecules, was developed shortly thereafter and, since it was patterned after Southern blotting, its name was a humorous play on words inspired by the name...