Work

An organism's genome is stored in the form of long rows of building blocks, known as nucleotides, which form DNA molecules. In the late 1960s, Werner Arber discovered substances known as restriction enzymes, which cut DNA molecules at sites where a certain sequence of nucleotides occurs. The discovery of restriction enzymes opened the way to explaining in which order genes exist on the chromosome, to investigating genes' chemical composition, and to putting DNA together in new combinations.