10 Differences between Southern Blotting and Western Blotting

Southern blotting: The Southern blot is used to detect the presence of a particular DNA fragment in a sample.The technique was developed by E.M. Southern in 1975.

Western Blotting: Technique for detecting specific proteins separated by electrophoresis by use of labelled antibodies. The technique was developed by Towbin et al in 1979.

 Southern Blotting VS Western Blotting

Southern Blotting	Western Blotting
Technique for the identification of specific DNA in a sample	Technique for the identification of specific protein in a sample
Developed by E.M. Southern therefore called “ Southern”	The term “Western” has no scientific significance just a misnomer to match with Southern blotting
Principle is Hybridization; the process of forming a double-stranded DNA molecule between a single-stranded DNA probe and a single-stranded target DNA. (Southern Blotting Steps)	Principle: Antigen-antibody interaction, an immunodetection method (Refer: Western Blotting)
Probe used is single stranded DNA or sometimes RNA	Probe used is antibodies specifically targeted against epitopes of antigens
DNA-DNA hybridization or RNA-DNA hybridization	Antibody-antigen complex formation
DNA fragments separated by Agarose gel electrophoresis	Proteins separated by SDS-PAGE (Sodium dodecyl sulphate-PolyAcrylamide Gel Electrophoresis)
DNA is denatured with an alkaline solution such as NaOH before blotting. This causes the double stranded to become single-stranded.	SDS denatures protein and imparts an overall negative charge
No such step as blocking (SouthernBlotting- Principle, Procedure and Applications)	Blocking nonspecific antibody sites on the nitrocellulose paper with bovine serum albumin (BSA) or milk powder
ssDNA or rarely RNA as probe	Probe include primary antibody followed by labelled secondary antibody
Common labeling methods include radio labeling or fluorescent labeling or use of chromogenic dyes. Southern vs Northern Blotting (Video)	Common labeling methods include horseradish peroxidase-anti-Ig conjugate or formation of a diaminobenzidine (DAB) precipitate (chromogenic dye), radiolabelling or use of fluorescently labelled secondary antibody.