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DNA and genetic code. Computer artwork of a section of beta DNA seen in front of its genetic code. Beta DNA (deoxyribonucleic acid), in which the double helix spirals clockwise when viewed from above, is the most common form of DNA. The genetic sequence, or fingerprint, of DNA can be determined by electrophoresis. First the DNA is cut into fragments by an enzyme and put in solution with a dye for sequencing. These fragments are then placed in an agarose gel. By electrophoresis, the application of an electric charge to the gel, the fragments separate into bands. Each band represents the position of one of the four bases that form the genetic code. (KEYSTONE/SCIENCE PHOTO LIBRARY/LAGUNA DESIGN)