Gel electrophoresis Gel electrophoresis:separates DNA molecules based on size Electrophoresis uses an electrical field to separate charged molecules 。 Gels are usually made of agarose,a polysaccharide 0 Nucleic acids migrate through gel toward the positive electrode due to their negatively charged phosphate groups Gels can be stained with ethidium bromide and DNA can be visualized under UV light Chen Feng,Lecture of MicrobiologyChen Feng, Lecture of Microbiology Gel electrophoresis Gel electrophoresis: separates DNA molecules based on size • Electrophoresis uses an electrical field to separate charged molecules • Gels are usually made of agarose, a polysaccharide • Nucleic acids migrate through gel toward the positive electrode due to their negatively charged phosphate groups Gels can be stained with ethidium bromide and DNA can be visualized under UV light