 The terms "northern", "western" and "eastern" blotting are derived from what initially was a molecular biology joke that played on the term "Southern blotting", after the technique described by Edwin Southern for the hybridisation of blotted DNA.Patricia Thomas, developer of the RNA blot which then became known as the "northern blot", actually didn't use the term.Named after its inventor, biologist Edwin Southern, the Southern blot is a method for probing for the presence of a specific DNA sequence within a DNA sample.