And by that method, we can essentially produce many copies of that DNA of interest, the recombinant DNA molecule. Now, in biochemistry, there are two types of plasmids that we commonly use. So we use PBR three, two, two, and we also use PUC 18. So let's begin by discussing PBR three, two, two. Now, this was one of the first plasmids that was used to basically clone make many copies of the recombinant DNA molecules. Now, this is what the plasma actually looks like.