∞ generated and posted on 2016.08.28 ∞

Self-duplication of genotype-carrying molecules, or of the cells or organisms carrying this hereditary material.

Genotype usually consists of DNA, or occasionally of RNA (as is the case with numerous viruses). The job of replication is to produce exact duplicates of the double helix of DNA or equivalent of RNA for RNA viruses. DNA begets DNA begets DNA.

With cellular organisms, for which universally the hereditary material consists of DNA, this act of DNA duplication not only is replication but is the core basis of reproduction: Making copies of DNA (replication) is the essential first step in producing progeny organisms (reproduction) or, indeed, in simply making more cells (growth).

Among numerous proteins required for replication, the most central is the polymerase, i.e., various DNA polymerases for DNA replication. Alternatively, various RNA polymerases are used for the replication of the genomes/chromosomes of RNA viruses.


Figure legend: Many facets of the idea of replication going from duplication of genetic material (here DNA) to duplication of cells to further increases in the number of cells (growth) to individual organisms producing progeny, that is, new individual organisms (reproduction). The usage, however, is commonly limited to the duplication of genetic material and individual cells.

To reiterate and expand, the term replication actually has a least three meanings. Starting from the most basic, from molecular genetics, it is the templated duplication of genetic material, DNA or in the case of some viruses, RNA, i.e., as indicated above. In terms of cell biology, it is the generation of a new daughter cell or cells from an existing parental cell via processes known as mitosis, meiosis, or binary fission. At a still higher, organismal level, it is the generation of progeny individuals by either sexual or asexual means. The two latter meanings also, and perhaps preferably, can be described instead as cell division, reproduction, proliferation, or even growth.