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Purebred



Purebreds, also called purebreeds, are cultivated varieties or cultivars of an animal species, achieved through the process of selective breeding. When the lineage of a purebred animal is recorded, that animal is said to be pedigreed.

The term purebred is occasionally confused with the proper noun Thoroughbred, which refers exclusively to a specific breed of horse, one of the first breeds for which a written national stud book was created, a purebred animal that has had meticulously documented pedigrees and a closed stud book since the 18th century. Thus a purebred animal should never be called a "thoroughbred" unless the animal actually is a registered Thoroughbred horse.

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Breeding true

In the world of animal breeding, to "breed true" means that specimens of an animal breed will breed true-to-type when mated like-to like; that is, that the progeny of any two individuals in the same breed will show consistent, replicable and predictable characteristics. A puppy from two purebred dogs of the same breed, for example, will exhibit the traits of its parents, and not the traits of all breeds in the subject breed's ancestry.

However, over time, there are also concerns that breeding from too small a gene pool can lead to inbreeding and the development of negative characteristics or even a collapse of a breed population due to inbreeding depression. Hence, there is continuing tension within many purebred animal breeds over the question of when a breed may need to allow "outside" blood in for the purpose of improving the overall health and vigor of an animal breed.

Pedigrees

A pedigreed animal is one that has its ancestry recorded. Often this is tracked by a major registry. The number of generations required varies from breed to breed, but all pedigreed animals have papers from the registering body that attest to their ancestry.

Sometimes the word purebred is used synonymously with pedigreed, but not all purebred animals have their lineage formally recorded. For example, until the 20th century, the Bedouin people of the Arabian peninsula only recorded the ancestry of their Arabian horses via an oral tradition, supported by the swearing of religiously-based oaths as to the asil or "pure" breeding of the animal. Conversely, some animals may have a recorded pedigree or even a registry, but not be considered "purebred." Today the modern Anglo-Arabian horse, a cross of Thoroughbred and Arabian bloodlines, is considered such a case. Thus, not all pedigreed animals are purebred, nor are all purebreds pedigreed.

Purebred dogs

In the hobby of dog breeding, the word purebred causes controversy, largely because of unresolved differences of opinion over what constitutes a dog breed. Critics also point to the fact that closed registries ensure that only genetically similar dogs may be bred. Many of these organizations also permit inbreeding which may result in many of the genetic disorders found among purebred dogs such as canine hip dysplasia.

In general, there are two types of purebred dog breeds: those recognized by a kennel club and those of independent breed clubs.

Kennel clubs, like breed registries for other animals, usually have strict sets of criteria for the recognition of a new or existing dog breed, normally with some period of developmental or provisional status. It cannot be assumed that the date of recognition of a breed indicates how long the breed has existed as a pure breed.

Independent purebred breeds are typically dogs of renown in their originating countries, usually with a long history of breeding true to type. They may remain independent due to any of the following reasons:

  • The lack of a national kennel club or low interest in dog fancy in smaller nations.
  • The dogs being so venerable in the eyes of their breeders and owners that there is no reason to seek outside affiliation.
  • The desire to preserve independent control over the attributes of the breed.
  • Concern over the decline of working breeds following kennel club recognition.

Recently, proposed breed-specific legislation has threatened the existence of independent dog clubs, as the fanciers of independent breeds are forced to seek alliance with kennel clubs to preserve their dogs' purebred status.[citation needed]

There is controversy over certain types of hybrid dogs, and whether these animals constitute a breed. Some hybrid breeders are trying to get kennel clubs to recognize breeds such as the "Pekapoo" and the "Cockapoo" which have been bred for more than 50 years and many have known lineage and pedigrees. Many were created using purebred dogs of different breeds, often registered animals.

Purebred horses

According to the "Four Foundations" theory, the evolution of the horse ultimately produced horses of four basic body types, adapted to different environments. Beginning with the may have been bred true to original type by humans, though emphasizing certain inherent traits (such as a good temperament, suitable to training by humans) to a greater degree than others. In other cases, horses of different body types were cross bred until a desired characteristic was achieved and bred true.

Written and oral histories of various animals or pedigrees of certain types of horses have been kept throughout history, though breed registry stud books trace only to about the 13th century, at least in Europe, when pedigrees were tracked in writing, and the practice of declaring a type of horse to be a breed or a purebred became more widespread.

Certain horse breeds, such as the Andalusian horse and the Arabian horse, are claimed by aficionados of the respective breeds to be ancient, near-pure descendants from one or the other of the original four wild prototypes, though absent a full mapping of the horse genome and other DNA research, such claims are difficult to prove or disprove.

Purebred cats

Many cat breeds are also recognized as breeding true to type and have registries to preserve their breeding records.

Purebred livestock

Most domesticated farm animals also have true-breeding breeds and breed registries, particularly cattle, sheep, goats, rabbits, and pigs. While animals bred strictly for market sale are not always purebreds, or if purebred may not be registered, most livestock producers value the presence of purebred genetic stock for the consistency of traits such animals provide. It is common for a farm's male breeding stock in particular to be of purebred, pedigreed lines.

Wild species, Landraces, and Purebred species

See also: Genetic pollution and Landrace

Breeders of purebred domesticated species discourage crossbreeding with wild species, unless a deliberate decision is made to incorporate a trait of a wild ancestor back into a given breed or strain. Wild populations of animals and plants have evolved naturally over millions of years through a process of Natural selection in contrast to human controlled Selective breeding or Artificial selection for desirable traits from the human point of view. Normally, these two methods of reproduction operate independently of one another. However, an intermediate form of selective breeding, wherein animals or plants are bred by humans, but with an eye to adaption to natural region-specific conditions and an acceptance of natural selection to weed out undesirable traits, created many ancient domesticated breeds or types now known as landraces.

Many times, domesticated species live in or near areas which also still hold naturally evolved, region-specific wild ancestor species and subspecies. In some cases, a domesticated species of plant or animal may become feral, living wild. Other times, a wild species will come into an area inhabited by a domesticated species. Some of these situations lead to the creation of hybridized plants or animals, a cross between the native species and a domesticated one. This type of crossbreeding, termed genetic pollution by those who are concerned about preserving the genetic base of the wild species, has become a major concern. Hybridization is also a concern to the breeders of purebred species as well, particularly if the gene pool is small and if such crossbreeding or hybridization threatens the genetic base of the domesticated purebred population.

The concern with genetic pollution of a wild populaton is that hybridized animals and plants may not be as genetically strong as naturally evolved region specific wild ancestors wildlife which can survive without human husbandry and have high immunity to natural diseases. The concern of purebred breeders with wildlife hybridizing a domesticated species is that it can coarsen or degrade the specific qualities of a breed developed for a specific purpose, sometimes over many generations. Thus, both purebred breeders and wildlife biologists share a common interest in preventing accidental hybridization.

See also

 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Purebred". A list of authors is available in Wikipedia.
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