Now, the question is, how can we go about amplifying that gene of interest? Well, one way that we spoke about earlier is to basically take that gene to integrate that gene into a bacteria plasmid, to place that recombinant plasmid into a bacterial cell, and then to allow that bacterial cell to divide many, many times and eventually we form many copies of that gene of interest. Now, the problem with that method is it's not only time consuming and not only is it ineffective, but it also limits the size of that gene that we can actually use. A much more effective and a much more efficient and accurate method is the polymerase chain reaction, or PCR. Now, the polymerase chain reaction allows us to amplify a certain gene, a certain sequence of DNA, very quickly. So we can produce millions or even billions of copies of a single segment of DNA that we're actually interested in.