And we can isolate these blue sections, these recombinant DNA molecules. And now we have many, many copies of these DNA molecules, recombinant DNA molecules that we can actually work with. So we see that to form recombinant DNA molecules, we actually mean restriction enzymes. And one way to amplify the recombinant DNA that we form is by using these plasmids. Now, another way we'll be focused in a different lecture. So this method actually has one important limitation and that's the size of that recombinant DNA.