Though groups like the American Kennel Club make very specific designations about breeds and breed hybrids, there continue to be new breeds and breed variants developed all the time, as well as "up and coming breeds" not officially recognized by kennel clubs and experts. (Many dogs not purchased directly from breeders are also mixed-breeds of some kind, or have less than purebred ancestry.)
If you own one of the 11 "riskiest" dog breeds -- which include Rottweilers, Pit Bulls and Doberman Pinschers -- you may face some big homeowners or renters insurance headaches, even if the only things your pup has ever taken a bite of are his Alpo and bone. These days, companies offering homeowners and renters insurance are pickier than ever about which types of dogs they’ll insure and which they won’t
For example, a bill currently under consideration in New Jersey would ban breeders from selling dogs outside the state unless the sale was made face-to-face. If you are a breeder in New Jersey and a potential buyer in say, California, is interested in one of your dogs, this buyer would have to come to New Jersey to see and buy the dog. Or the breeder would have to take the dog to California. This is obviously onerous and unnecessary. It also adds a tremendous expense to the cost of the dog. This kind of legislation is proposed in the name of “consumer protection” but it is actually meant to punish and discourage dog breeding.
Dogs have been selectively bred for thousands of years, sometimes by inbreeding dogs from the same ancestral lines, sometimes by mixing dogs from very different lines. The process continues today, resulting in a widening in appearance without speciation, "from the Chihuahua to the Great Dane."