The AKC, or American Kennel Club, has stringent rules regarding breeding of its dogs, including DNA profiling. The Continental Kennel Club (CKC) is more lenient with breed registrations and breeding regulations. For pure bloodlines and certified breeding practices, the AKC is clearly better.
The AKC was started in 1884. In order to be registered with the AKC, both of the dog's parents must be registered, as well as their parents, and so on. Every dog that is AKC certified can trace its lineage to the start of the AKC. The AKC also regularly inspects the facilities of its breeders.
Almost any dog, including mixed breeds, can be registered with the CKC.