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On the Varieties of Dog Breeds

February 28, 2018

The Empress Dowager Cixi is known to Westerners from the movie The Last Emperor. In the early scenes of the film you see her holding court in the dying days of Imperial China, which was in sharp decline after 2,000 years of dynastic decadence. Amidst the ancient rituals of the Chinese Court, outsiders observed Cixi’s love of dogs, in particular of the Shi Tzu. The Shi Tzu dog breed is as old as Imperial China. The tiny ones that Cixi was reputed to have secreted in her sleeves have only the vaguest resemblance to the wolves which roamed the Mongolian steppes bordering China. How could this toy of a dog breed come about? The answer is that the Shi Tzu is a breed. And dog breeds come in an amazing variety of sizes and colors. Because of these breeds, dogs are in fact the most variable mammals on this planet.

All about Breed

So what is a breed? It is what breeders say it is. Breeds are not timeless categories, but populations which came into being over time through natural or artificial selection. Today 400 dog breeds are recognized by the Fédération Cynologique Internationale. And kennel clubs have developed many pure breeds. The individuals are defined by pedigree books which precisely delimit their lineage of ancestors and relations.

But not all breeds are created alike, nor were they created at the same time. Some dog breeds have ancient, distinguished histories which go back into deep antiquity. Instead of pedigree books, these breeds were formed based on their skills (like hunting) or traits. The sleek Saluki may have been hunting with the Sumerians 5,000 years ago, but it only got a pedigree book in the last 200 years.

Working Dogs

Functional and working dog breeds often have deep histories because of their role within the human system of economic production. This crystallized with the rise of agriculture in the Middle East 10,000 years ago. The development of complex societies saw dogs switch from being purely being generalist hunting companions and beasts of burden. They developed some lineages which were being transformed into human tools. Soon there were hounds to hunt with kings, mastiffs to march with armies, sheepdogs to guard our ancestors’ herds, and dogs to do menial tasks that pulling sleds or turning spits.

And yet most of the familiar breeds which we would recognize in all their unique doggy forms emerged in the last few centuries. In particular this occured during the Victorian period in England. These breeds serve different roles from the more ancient working dogs. Humans often used them for companionship or aesthetic characteristics. Perhaps this can explain the relationship between Paris Hilton and her late beloved chihuahua, Tinkerbell, a latter day Cixi and her sleeve Shih Tzu.

Ancient vs. Modern

Ancient dog breeds formed based on functional traits and not closed breed books are genetically different than breeds which are relatively new, and selected for specialized, usually aesthetic characteristics. Variation across lineages accumulates as a function of time between when those lineages separated. If the lineages are old, then there has been a lot of time for genetic variation to build up through mutation. This means that detection of distinctive ancestry is relatively easy because genetic patterns differ between two populations. No would confuse a Basenji with a German Shepard if they looked just at DNA.

In contrast, most modern breeds developed over the past century or so. Nevertheless, these breeds also quite distinct genetically. This is because the relatively small number of founding individuals and the strong selection towards a breed standard has driven less genetic differentiation at a rapid rate. Breeds have a great deal of history encoded in their genes. A powerful DNA test teases apart all that history and help you understand your dog’s unique story.