Samples of DNA (Deoxyribo nucleic Acid) are loaded into an agarose gel for separation by electrophoresis. A pipette is seen dispensing a DNA sample into a well of the gel (at upper right). Loaded samples are blue-filled wells running from far left to upper right. DNA samples seen here contain many fragments of "chopped" DNA. Blue dye is added to the DNA samples to help with visualisation while loading the gel. DNA fragments are separated by applying an electric current across the gel. Smaller fragments will move faster through the gel and become separated from larger fragments over time. This technique is used in gene cloning.