A collection of collections, a specialization of breed. Each pure breed is a collection of dogs belong to a single pure breed, recognized conventionally. To be recognized as a pure breed, a group of dogs must be sufficiently similar in genetics and in comformation to an accepted breed standard that a mating of any two dogs belonging to the breed produces offspring who also conform to that standard. In general, popular acceptance of a group of dogs as a pure breed also depends on the recognition of the breed by some organization that has dog breeding and standards as its focus, such as the The American Kennel Club. Except in unusually isolated environments, this type of genetic uniformity does not occur naturally in domestic dogs. Most instances of pure breed are the result of intentional design and action by some human.