And so what that means is if we can extract and collect these restriction enzymes we basically have a very efficient way of cleaving our DNA molecules at specific locations. So, for instance, if we want to study the following DNA molecule we can cut it up into many small fragments by using restriction enzymes and then we can analyze and study and manipulate and amplify all these different types of fragments. In fact, we can use these fragments to essentially sequence DNA molecules and that leads us directly into factor number two. So we are now able to actually determine exactly what the sequence of nucleotides is in any DNA molecule. Now, how is that useful in itself? Well, if we want to study a specific gene we have to know what the sequence of nucleotides is in that gene.