This article is about biological strains. For other uses, see strain. In biology, strain is a low-level taxonomic rank used in three related ways.
Microbiology/Virology
A strain is a genetic variant or subtype of a microorganism (e.g. virus or bacterium or fungus). For example, a "flu strain" is a certain biological form of the influenza or "flu" virus. Compare clade.
Plants
The term has no official ranking status in botany; The term refers to the collective descendants of a common ancestor and is sometimes used to designate a group that has descended from a modified plant by conventional breeding or more often by biotechnological means. Strains might produce one or many commercially desirable descendants, and if introduced into cultivation, they each are given cultivar names. Strains may be produced by hybridization or by engineered means. As an example, types of rice strains are made by inserting new genetic material into a rice plant,[1] all the descendants of the genetically modified rice plant are a strain with a unique genetic code that is passed on to later generations; it can be given a strain designation (normally a number or a formal name) the plants in the strain can then be breed to other rice strains or cultivars and if desirable plants are produced, these are further breed to stabilize the desirable traits and then given a cultivar name and released into production to be used by many farmers.
Rodents
A mouse or a rat strain is a group of animals that is genetically uniform. Strains are used in laboratory experiments. Mouse strains can be inbred, mutated or genetically engineered, while rat strains are usually inbred.
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