Well, we have to carry out a process known as southern Blotting. In southern Blotting we essentially use gel electrophoresis as we'll see in just a moment to basically identify and isolate a specific DNA fragment of interest. So let's begin with step number one. So we take our double stranded DNA molecule that contains the gene that we want to study. Now we know what the sequence of nucleotides within that gene is before we actually carry out that process and we'll see why that's important in step three. So we take the DNA, the double stranded DNA molecule, we expose it to specific restriction enzymes so that when they clean that DNA molecule one of these fragments will carry that gene of interest.