Gene amplification occurs when the number of copies of a gene sequence is increased. The term can refer to natural processes, such as the production of multiple copies of genes by cancer cells as they respond to signals from other cells. It can also refer to a laboratory technique used to increase the number of gene sequences in a test tube.
The natural form of gene amplification is referred to specifically as "gene duplication," while the synthetic gene amplification is known as a "polymerase chain reaction."
Gene duplication is the primary way in which new genetic material is created as part of molecular evolution. It can result from a variety of errors in DNA replication and repair mechanisms. The gene duplication usually does not cause a lasting change in the genome of a species and disappears with the death of the host organism.
Polymerase chain reactions are undertaken in a laboratory to increase the number of copies of a piece of DNA by several orders of magnitude. A single piece of DNA can be used to generate thousands of copies. This technique was developed in 1983. It is now a common part of research in medical and biological labs. There are two steps in the polymerase chain reaction technique. First, the two strands of the helix that make up DNA are separated. Second, those strands are used as templates by which the polymerase enzyme produces multiple copies.