Over the weekend I watched the National Geographic documentary “The Science of Dogs.” It explored canine genetics, studying what it is about a dog’s DNA that makes it the species with the greatest number of breeds.
The documentary revealed that there is something uniquely malleable about canine DNA that allows it to make a staggering variety of small changes. The example given by the documentary explained that one can breed cows in such a way to get different color patterns or shapes of horns. But all cows will look fundamentally the same and share identical characteristics.
As we well know, that is not true with dogs. Dogs come in all shapes, sizes, and colors, and with myriad and sometimes vastly different skills. Dogs are the only species on the planet whose genetics allow them such variety.
Of the over 500 dog breeds currently in existence, more than half have only existed for the past 100-plus years. For centuries, domesticated dogs closely resembled their wild ancestors and cousins in general looks and behavior. Yes, they were tame and enjoyed human company, but their roots showed much more clearly than one sees with current domestic animals.
The Industrial Revolution, as it did for so many other technologies, changed all of that. A growing middle class became accustomed to being able to tailor things to their specific needs. It wasn’t long until their attentions turned toward doing that to their dogs.
Dog breeding and eugenics—the science of engineering DNA through selective breeding to incorporate or enhance certain traits—became a Victorian-era fad. In just 100 years the number of dog breeds skyrocketed, and it is in this period that many well-known breeds, such as bulldogs and bull terriers, originated.
The trend, however, isn’t over. Over in Russia an employee of an airline has developed a new breed meant specifically for bomb-sniffing. Over the last two decades he’s crafted this specimen, combining various dogs with jackals to create the world’s best domesticated sniffer dog. Only 40 of the Sulimov dogs, named for their breeder, exist. As they are rare and property of the Russian government none have been permitted to leave the country.
Interestingly, this flexible DNA is a trait specific to the domesticated dog. They didn’t inherit it; DNA studies of wolves show that their genes do not possess the same flexibility. This is a trait that must have developed during or after the process of domestication.
However, geneticists don’t know what exactly it is about that process that caused the change. All we know is that changing characteristics through breeding forces a type of mutation, one that can sometimes have unpredictable side effects.
Anyone familiar with dogs or not could still easily list a number of differences between a domesticated dog and wolves. Researchers looking for answers to the above question, while they might not have yet found its exact answer, have managed to pinpoint the main difference.
By submitting dogs and a pack of domesticated wolves to a series of the same tests, they’ve managed to boil down the essential difference in the two species to a single concept: while wolves have each other for a pack, in the process of domestication humans replaced canines as a single dog’s pack members. When a domesticated dog is stumped by a task it looks to humans for direction, whereas wolves stymied by the same task pay no heed to nearby humans and just become frustrated.
In forming the deep bond we now share with dogs, humans somehow created the infinitely customizable animal. Man’s best friend, indeed.