What are the differences between Southern, Northern, and Western blotting?

These blotting techniques detect different molecules. Southern blotting (named after Edwin Southern) detects specific DNA sequences: DNA is restriction-digested, separated by gel electrophoresis, transferred to a membrane, and hybridized with a labeled probe. Northern blotting (named by analogy) similarly detects RNA to analyze gene expression. Western blotting (also named by analogy) detects proteins: samples are separated by SDS-PAGE, transferred to membrane, and detected using specific antibodies. Each technique combines electrophoretic separation with specific probe detection, enabling identification of target molecules in complex samples.