So what that means is the lambda phage virus does not need its own DNA to actually survive. We can put in any DNA as long as the size it's pretty much the same as the size of that initial lambda DNA. So to see how we can actually do that, let's take a look at the following diagram. So, in diagram one, we extract this blue DNA, the lambda DNA molecule, as shown in the following diagram. So first we need to cut the lambda phage with a restriction enzyme. So we choose some type of restriction enzyme.