And so eventually, we synthesize these complementary viral DNA molecules and once they separate, once they anneal, actually right, so once these two blue strands actually separate, these two blue strands, because they're complementary with respect to one another, they can basically anneal. And to anneal means to combine to form that double helix structure. And once we form the viral double stranded DNA molecule, that DNA molecule is brought into the nucleus of the cell. And inside the nucleus, a second type of special protein enzyme known as integrase, basically cuts the host DNA molecules. So the green DNA is the host DNA, it cuts a section of that DNA molecule, it opens it up, and this double stranded DNA molecule that came from the virus basically injects itself integrates with that host DNA. And this is how the majority of retroviruses actually work.