Strain (biology)

In biology, strain is used in three related ways.

Microbiology/Virology
A strain is a genetic variant or subtype of a virus or bacterium. For example, a "flu strain" is a certain biological form of the influenza or "flu" virus. Compare clade.

Plants
A strain is a group of plants with similar (but not identical) appearance and/or properties. The term has no official status. See cultivar.

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.