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. So let's suppose we break it down into five different fragments and these fragments differ in their size. So we have the largest fragment of fragment A, we have the smallest fragment of fragment E and the fragment in between these fragments in terms of their size is fragment C. And that's the fragment, let's say, that contains the gene that we want to actually study. So fragment C is that DNA fragment, that restriction fragment that we actually want to identify and then separate.