So let's take a look at the following seven steps that basically describe how to build a genetic library. And for simplification purposes, we're going to examine a hypothetical organism that has a DNA that only consists of four different types of genes. So let's take the following DNA of some hypothetical organism that consists of gene one shown in green, gene two shown in purple, gene three shown in red and gene four shown in orange. 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.