Well, in biochemistry there's a process known as the polymerase chain reaction or PCR that allows us to do just that. So the polymerase chain reaction is a very effective method by which we can actually amplify make many copies of a single DNA segment. And it's very useful because it allows us a very quick way to make millions or even billions of copies of a single DNA molecule. It also allows us to make copies of a gene or DNA segment that is relatively long, about 10,000 nucleotides in length. And it also allows us to make the copies without actually knowing what the sequence of nucleotides in that gene is, as long as we know what the flanking sequence is. So we have to know what the flanking sequence is because we have to build DNA primers for the DNA replication process, as we'll see in just a moment.