So as always, we're dealing with a double helix DNA molecule that consists of these two individual single strands that run an antiparallel direction. So the first step in building our genetic library is to use these restriction enzymes that we spoke of in the previous lecture. So we basically pick a special type of restriction enzyme that is capable of cleaving of cutting this DNA molecule exactly at the locations where each gene begins and the other gene ends. So we cleave it right here, we cleave it right here as well as right here. So at the end, we basically produce the following four individual genes. So step number one, we cut our DNA molecule of that organism with a restriction enzyme.