Now, once we synthesize that DNA molecule of interest, what do we do next? Well, that leads us into factor number four. We have a process known as the polymerase chain reaction or simply PCR that allows us to amplify a single DNA molecule. That is, make many, many copies of that single molecule that we want to study. In fact, PCR allows us to make millions and billions of these copies from a single individual DNA molecule. So if we synthesize that fragment of DNA by using this solid state method we can then amplify the DNA and produce many, many copies of that DNA molecule.