- This article focuses on selective breeding in domesticated animals. For alternate uses, see artificial selection.
Selective breeding in domesticated animals is the process of a breeder developing a cultivated breed over time, and selecting qualities within individuals of the breed that will be best to pass on to the next generation. The term is synonymous with "Artificial selection". Breeding techniques such as inbreeding, linebreeding and outcrossing are utilized by breeders in the maintenance and improvement of their chosen breeds.
Charles Darwin discussed how selective breeding had been successful in producing change over time in his book, Origin of Species. The first chapter of the book discusses selective breeding and domestication of such animals as pigeons, dogs and cattle. Selective breeding was used by Darwin as a springboard to introduce the theory of natural selection, and to support it.
"Breeding stock" is a term used to describe a group of animals used for purpose of planned breeding. When individuals are looking to breed animals, they look for certain valuable traits in purebred
stock for a certain purpose, or may intend to use some type of crossbreeding
to produce a new type of stock with different, and presumably superior abilities in a given area of endeavor.
For example, to breed chickens, a typical breeder intends to receive eggs, meat, and new, young birds for further reproduction. Thus the breeder has to study different breeds and types of chickens and analyze what can be expected from a certain set of characteristics before he or she starts breeding them. Accordingly, when purchasing initial breeding stock, the breeder seeks a group of birds that will most closely fit the purpose intended.
Mating animals of the same breed for maintaining such breed is referred to as purebred breeding. Opposite to the practice of mating animals of different breeds, purebred breeding aims to establish and maintain stable traits, that animals will pass to the next generation. By "breeding the best to the best," employing a certain degree of inbreeding
, considerable culling, and selection for "superior" qualities, one could develop a bloodline or "breed
" superior in certain respects to the original base stock.
Such animals can be recorded with a breed registry, the organisation that maintains pedigrees and/or stud books.
The observable phenomenon of hybrid vigor stands in contrast to the notion of breed purity. However, on the other hand, indiscriminate breeding of crossbred or hybrid animals may also result in degradation of quality.
The term backyard breeder is a general term, sometimes considered derogatory, used in USA
to describe people who breed animals without selection for important genetic traits. Usually describes those who allow animals, particularly dogs or horses, to procreate regardless of physical or genetic health as opposed to breeders who intentionally screen and select their brood for important characteristics.
Selective breeding is also used in research to produce transgenic
animals that breed "true" (i.e. are homozygous
) for artificially inserted or deleted