Gel electrophoresis is a tool of molecular biology that is used to compare the DNA of two individuals. Gel electrophoresis seperates biomolecules such as DNA, RNA, or protiens into fragments. Restriction enzymes are utlized to do this. Restriction enzymes cuts the DNA at specific nucleotide sequences called restriction sites. Once the DNA has been cut into fragments, it is placed a slab of agar gel. Each well can house the DNA of different individuals. An electrical current is then run through the gel. The fragements seperate based on size and charge- the smaller traveling farther and the negative being pulled further along toward the positive charge at the base of the gel slab (recall that opposites attract). Because no two organisms (except identical twins) have the exact DNA, each person's DNA fragments seperate differently. The more simular fragments that two individuals share, the more closely related they are.