are the most common subjects of eukaryotic genetic modification, especially with respect to industrial fermentation. 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 laboratory mouse or 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 modified, while rat strains are usually inbred. A given inbred rodent population is considered genetically identical after 20 generations of sibling-mating. Many rodent strains have been developed for a variety of disease models, and they are also often used to test drug toxicity. Insects The common fruit fly (Drosophila melanogaster) was among the first organisms used for genetic analysis, has a simple genome, and is very well understood. It has remained a popular model organism for many other reasons, like the ease of its breeding and maintenance, and the speed and volume of its reproduction. Various specific strains have been developed, including a flightless version with stunted wings (also used in the pet trade as live food for small reptiles and amphibians). See also Genetic isolate Clone (cell biology) Race (biology) Variant (biology) References External links Coli Genetic Stock Center EcoliWiki E. coli strain index International Mouse Strain Resource (IMSR) Rat strain index Microbiology terms Virology Taxa by rank Infraspecific virus taxa