Amplification: Function, Tasks, Role & Diseases

Amplification means the multiplication of segments of deoxyribonucleic acid (DNA). These can be molecules, individual genes, or even larger parts of the genome. Amplification occurs as a natural duplication of sequences of DNA as the carrier of hereditary information. Thus, it is one of the most important categories in the theory of heredity (genetics).

What is amplification?

In the laboratory, amplification is artificially applied as a technical procedure in molecular biology. The starting sequence in this process is the amplicon, and the result is ultimately the amplicon. As a natural process, amplification is a form of mutation, that is, the permanent change of the genetic material. In this way, it can serve to accelerate evolution by spreading and condensing certain DNA segments in the genome. For example, resistance to antibiotics or insecticides is developed by shortened pathways. It is also possible to use the selective duplication of genes to increase their degeneracy for when they are needed. This is done, for example, in oocytes so that they can meet their increased demand for ribosomes. In some natural amplifications, replication is applied to genes multiple times. Electron microscopy has revealed an onion skin structure in this event, for which technical language has coined the term “onion skin replication.”

Function and task

Nucleotides are basic building blocks of nucleic acids, in the case of DNA as well as RNA (ribonucleic acid). They consist of a phosphate part, a sugar part, and a base part. In their nature, these molecules are extraordinarily diverse and fulfill important regulatory functions in cells, especially with regard to metabolism. Nucleotides link the sugar to the base and the phosphate to the sugar by means of an ester bond. It is also possible to attach more than one phosphate to the sugar. The nucleotides can be distinguished by the bases they contain and the sugar. In DNA, this is deoxyribose; in RNA, it is ribose. In total, the large molecules DNA and RNA are each composed of four different types of nucleotides, which can be arranged next to each other in any way. This happens by means of a coding reaction. In order to provide the information necessary to encode the genetic message, at least three nucleotides must join together. In this way, they form a single strand of DNA. To create the double strand, the single strand is mirrored. Each arranged base of the single strand is opposite a complementary base of the mirrored strand. In the respective base arrangement, there is again a regularity that depends on the chemical nature of the concrete pair. Both DNA strands that belong together form the so-called double helix. The opposite bases of the nucleotides are connected by hydrogen bonds. Depending on the base pair, two or three of these hydrogen bonds are built. This process is called base pairing in cell biology. In this context, amplification also enables the exact replication of existing structures in the human cell. If this can be artificially controlled, it will be possible to treat certain cancers in a more targeted manner in the future. One technology for DNA amplification in the test tube (in vitro) is the so-called polymerase chain reaction (PCR). It can be used to amplify any DNA segment in a short time and in a simple way.

Diseases and disorders

In some circumstances, so-called cancer genes (oncogenes) are induced to grow unchecked by amplification. Similarly, some oncogenes respond to certain cytostatic drugs (natural or artificial substances that inhibit cell growth) with amplification. Accordingly, in cancer therapy, those special agents are used as cytostatics which block the production of building blocks of nucleic acids. The cancer cells, in turn, are able to react to this by amplifying gene parts that are inhibited by cytostatic drugs. The oncocells often form homogeneous chromosome extensions.