DNA When charged molecules are placed in an electric field, they migrate toward either the positive or negative pole according to their charge. In contrast to proteins, which can have either a net positive or net negative charge, nucleic acids have a consistent negative charge imparted by their phosphate backbone, and migrate toward the anode DNA is electrophoresed through the agarose gel from the cathode (negative) to the anode (positive) when a voltage is applied, due to the net negative charge carried on DNA.
