Strain (biology)

This article is about strains in taxonomy. For biomolecular strain, see Strain (chemistry).

In biology, a strain is a low-level taxonomic rank used in three related ways, usually at the infraspecific level (within a species).

Microbiology or virology

A strain is a genetic variant or subtype of a micro-organism (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 produced from a common ancestor that share a uniform morphological or physiological character. A strain is a designated group of offspring that are either descended from a modified plant (produced by conventional breeding or by biotechnological means), or which result from genetic mutation.

As an example, some rice strains are made by inserting new genetic material into a rice plant, all the descendants of the genetically modified rice plant are a strain with unique genetic information that is passed on to later generations; the strain designation, which is normally a number or a formal name, covers all the plants that descend from the originally modified plant. The rice plants in the strain can be bred to other rice strains or cultivars, and if desirable plants are produced, these are further bred to stabilize the desirable traits; the stabilized plants that can be propagated and "come true" (remain identical to the parent plant) are given a cultivar name and released into production to be used by 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.

See also

• Genetic isolate
• Race (biology)

External links

• Coli Genetic Stock Center
• EcoliWiki E. coli strain index
• International Mouse Strain Resource (IMSR)
• Rat strain index