At the 140th Westminster Kennel Club Dog Show in New York City on Tuesday, almost 200 different dog breeds competed for Best in Show, including seven newly minted breeds. In fact, almost every year for the past decade, new breeds have been added to the American Kennel Club's (AKC) registry of 189 "approved breeds."
Leading up to the show, Motherboard headed over to Meet The Breeds, an event held the weekend before where the public can canoodle with their favorite pups, and learn about each dog's historical origins. We were blown away by the genetic diversity of this single species, Canis lupus familiaris. So what's up with dog genetics? What makes a breed a breed?
In order for a breed to become approved, there must be a "sufficient population in the country (minimum of 300-400 dogs), with a three-generation pedigree," according to the AKC's guidelines. There also needs to exist a wide geographic distribution of the dog: There must be one pup of the new breed living in at least 20 different states.
Interestingly, a new breed of canine isn't denoted by a specific genetic profile, at least not by the AKC. Instead, "breed standards" are developed by clubs of dog breeding hobbyists. Breed standards outline the appearance, movement, and temperament of a dog breed, but they're not scientific documents by any means.
AKC offers DNA testing for dogs, and requires it in some circumstances, but the data the tests provide is only for "parentage verification and genetic identity purposes," and it is not "a breed identification test." In other words, the testing doesn't indicate what kind of dog a puppy is, but merely confirms who its parents are. As of 2014, the AKC reportedly has collected over 650,000 DNA profiles in its database.
Geneticists have only recently started to associate dog breeds with a specific genetic profile, which might indicate why the AKC is hesitant to use this form of classification. In 2004, researchers published the findings of a study comparing the genes of 85 common domesticated dog breeds in Science. One of the first times that a comprehensive study of the genes of dogs had been compiled, the study found that the majority of breeds have a unique DNA signature, even though many were only bred into existence in the last several centuries.
The distinction found between some of the breeds was greater than the difference between humans who live on different continents, indicating a high level of genetic difference between different breeds.
The proliferation of new breeds is in part a product of "linebreeding," a type of inbreeding in which a close relative occurs more than once in a puppy's pedigree. "This is standard practice," James A. Serpell, Director of the Center For The Interaction of Animals & Society at University of Pennsylvania, told me.
Linebreeding can cause high rates of genetic disorders, such as cancer. "Inbreeding inevitably results in nasty genetic mutations," Serpell told me. Over time, inbreeding magnifies specific traits within a lineage, causing for wide physical and behavioral differences between breeds.
While some genetic tests can help indicate what breeds are more likely to be diagnosed with certain diseases, it's often extremely complicated to account for all the factors involved. Developing genetics tests for canines is also expensive.
"You have to pay for geneticists to develop them, and most dog clubs don't have tons of money," Serpell said, "so even if they know there is a potential problem with a breed, most dog clubs don't have the resources to pay someone to develop the test."
While it can be difficult to assess whether or not a dog is susceptible to diseases based on their genetic profiles, collecting the DNA of dogs might help shed light on when humans domesticated them.
In 2015, researchers from Cornell University published the results of a seven-year study that analyzed data from dogs living in 38 countries across 6 continents. In total, they analyzed over 185,000 genetic markers from 549 village dogs, and concluded that dogs were most likely first domesticated in Central Asia, likely near Nepal or India.
This isn't the whole story, however. As The Atlantic pointed out, there have been a whole host of different studies, citing both ancient and current dog DNA, which link dogs to a wide range of places and time periods. Some studies indicate that dogs became domesticated during the Agricultural Revolution 10,000 years ago, but other genetic tests indicate that it might have happened far earlier, as much as 32,000 years ago, when humans were still hunter-gatherers.
No matter their genetic makeup, we loved all the dogs at Meet The Breeds. Now, meet our favorites: