And once we carry out step three, then we can use the process of order radiography and that will allow us to pinpoint exactly where that fragment is. And now we know if we go back to this setup, that this band C contains those fragments that we want to isolate. And so we can take out the fragments, remove the other unwanted fragments, and now we have a pure solution that contains only the fragment, only that gene that we were actually interested in the first place. So this process by which we can actually pinpoint, detect and then isolate that DNA fragment of interest by using our DNA probe is known as southern blotting. But we also can repeat the same exact process with RNA molecule. So if we have an RNA molecule that we actually want to isolate, we can use an RNA probe or radioactively RNA probe in the same exact process.