(August 2003) The separation of DNA/RNA fragments or a protein sample based on size can be useful in many applications, but visualizing samples on a gel does not give any information about the identity of the sample (i.e. which gene fragment, mRNA or protein you are looking at). So how can you pick out the band you’re interested in? E.M. Southern answered this question when he developed a method that was subsequently named after him, the Southern Blot. Figure 1. The layout for a Southern Blot. The Southern Blot takes advantage of the fact that DNA fragments will stick to…