Inbred strains are individuals of a particular species which are nearly identical to each other in genotype

Genotype

The genotype is the genetic makeup of a cell, an organism, or an individual usually with reference to a specific character under consideration...

 due to long inbreeding

Inbreeding

Inbreeding is the reproduction from the mating of two genetically related parents. Inbreeding results in increased homozygosity, which can increase the chances of offspring being affected by recessive or deleterious traits. This generally leads to a decreased fitness of a population, which is...

. Inbred strains of animals are frequently used in laboratories for experiments where for reproducibility of conclusions all the test animals should be as similar as possible. However, for some experiments, genetic diversity in the test population may be desired. Thus outbred strains of most laboratory animals are also available.

Certain plants including the genetic model organism

Model organism

A model organism is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the organism model will provide insight into the workings of other organisms. Model organisms are in vivo models and are widely used to...

 Arabidopsis thaliana

Arabidopsis thaliana

Arabidopsis thaliana is a small flowering plant native to Europe, Asia, and northwestern Africa. A spring annual with a relatively short life cycle, arabidopsis is popular as a model organism in plant biology and genetics...

naturally self pollinates, which makes it quite easy to create inbred strains in the laboratory (other plants, including important genetic models such as Maize require transfer of pollen

Pollen

Pollen is a fine to coarse powder containing the microgametophytes of seed plants, which produce the male gametes . Pollen grains have a hard coat that protects the sperm cells during the process of their movement from the stamens to the pistil of flowering plants or from the male cone to the...

 from one flower

Flower

A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...

 to another). For most animals, the usual procedure is mating of brother-sister pairs for 20 generations which will result in lines that are roughly 98% genetically identical. For most purposes this is sufficient to be considered an inbred strain (compare to identical twins or clones which are 100% genetically identical).

See also:

• Backcrossing
  Backcrossing
  Backcrossing is a crossing of a hybrid with one of its parents or an individual genetically similar to its parent, in order to achieve offspring with a genetic identity which is closer to that of the parent...
  
  
• Linebreeding
• Recombinant inbred strain
  Recombinant inbred strain
  A recombinant inbred strain is an organism with chromosomes that incorporate an essentially permanent set of recombination events between chromosomes inherited from two or more inbred strains...
  
  

The most well-known lines of laboratory animals are:

Rats

• Wistar as a generic name for inbred strains such as Wistar-Kyoto, developed from the Wistar outbred strains
• Sprague-Dawley
• Long-Evans