And so at the end, we're going to form this single molecule, single DNA molecule, that is a recombinant DNA molecule. It will consist of these individual DNA molecules that ultimately came from two different sources. So what scientists realized is once they actually discovered restriction enzymes, they then realized that they can use these restriction enzymes to basically form any recombinant DNA molecule that they actually want. Now the next question is, once they actually form that recombinant DNA molecule, how do you amplify your results? How do you produce many copies of that same recombinant DNA molecule? Because if you want to conduct many different types of experiments, you need many different copies of that same recombinant DNA molecule.