Home
science
News: JoAnna Lou
Humanity's Best Friend
We may owe our evolutionary success to the domestication of dogs

Scientists have long debated why Neanderthals lived successfully on earth for over 200,000 years and then died off after humans came along, about 40,000 years ago. Some blame it on climate change, while others think humans were more successful at getting food due to social cohesion and the ability to develop advanced tools.

However, a new theory claims that we may owe our evolutionary success to the domestication of dogs.

Anthropologist Pat Shipman speculates that the relationship between humans and canines began in hunting, where dogs would help people identify prey and haul carcasses back home on their backs (dogs of the Paleolithic era were typically the size of a modern-day German Shepherd or larger). This assistance gave humans an advantage in obtaining food and conserving energy.

Shipman believes that the relationship between humans and dogs only got stronger over time and may have even led to shared characteristics for communication. In humans, the whites in our eyes are highly visible, compared to other primates, allowing people to "talk" silently when hunting in groups. It turns out that canines, unlike other animals, have the ability to decipher our eye contact. In a study conducted at Central European University, dogs performed as well as human infants at following the gaze of a person when they held their head still.  

Because canines may play an important role in our success over Neanderthals, Shipman calls them "humanity's best friend." Dog lovers need no validation that our pets are critical in our lives, but now we may have more to thank them for than we previously thought!

Culture: Science & History
DNA Testing
Which DNA test should you choose to settle the “what’s in the mix” question?

For years, you’ve argued with your spouse that the 60-pound, black-and-tan tennis ball–chaser who takes you for walks and sweeps the coffee table clean with his tail is a German Shepherd mix, and that there is absolutely no Doberman Pinscher in there. Finally, in order to end the breed debate once and for all and restore peace to your household, you’ve decided to settle the question with a mixed-breed analysis test.

You’ve heard of the “swab test” and the “blood test” and know that both claim to unravel breed ancestry. With a little more research, you discover that the world of canine heritage tests has expanded since the first tests became available in 2007. Having a choice is great, but how do you go about comparing them and choosing the one that’s right for you?

There are several factors to consider, including the type of sample required, the number of breeds that can be identified, costs, turnaround times and the way the results are reported. Before you commit to a test that will decide the outcome of the German Shepherd/Doberman Pinscher battle, be sure you understand what you’ll be getting.

MetaMorphix Inc. (MMI) Genomics administers the Canine HeritageTM Breed Test, commonly referred to as “the swab test,” and Mars Veterinary provides “the blood test,” the Wisdom PanelTM MX Mixed Breed Analysis. These two companies have been considered the main players in this market, but new contenders are flocking to the scene. The most recent challengers are DNA Print Genomics, which offers the Doggie DNA Print, and BioPet Vet Lab, which recently unveiled the Dog DNA Breed Identification Test. Both use cheek swab samples.

The swab sample has the advantage of a collection procedure that is simple enough to be done by the owner at home. It does have some drawbacks, however, including a risk of contamination and too few cells being obtained for successful testing. To avoid the latter, BioPet Vet Lab includes a card that changes color to indicate that a sufficient sample is present. Blood samples are collected by a veterinarian and the chances of contamination and inadequate sample size are greatly reduced.

Tests also differ in the number of breeds available for comparison. Mars Veterinary interrogates the genetic signatures of more than 130 of the 159 breeds recognized by the American Kennel Club (AKC).* MMI Genomics recently announced the XL version of their test, which has a database of more than 100 breeds. The breed list available for BioPet Vet Lab contains 58 breeds. DNA Print Genomics does not report specific breed matches; rather, “15 elements of dog ancestry” are revealed, and the customer performs a search of the company’s online database to identify matches to particular breeds. Since each test interrogates a different set of breeds, sending your dog’s sample to more than one company may not return identical results.

Cost and turnaround times vary from test to test. In the past, the cost of the Wisdom Panel MX Mixed Breed Analysis test was determined solely by individual veterinary clinics, but the test can now be purchased online for $124.99, and test results are available within three to four weeks. (Your veterinarian will still have to draw the blood sample.) The swab tests are sent directly to the owners for sample collection, and prices and turnaround times vary: Doggie DNA Print, $199, six to nine weeks; Canine Heritage XL Breed Test, $119.95, four weeks (if you submitted a sample for the original version of the Canine Heritage Breed Test, you can purchase an upgrade to the XL version for $55 online); and the Dog DNA Breed Identification Test, $57.95 to $59.99, two weeks. (Prices current at press time.)

Results are presented as a certificate or report, depending on the company. MMI Genomics provides owners with a Certificate of DNA Breed Analysis. Three breed categories are included in the results: Primary, Secondary and In the Mix. BioPet Vet Lab’s Ancestry Analysis Certificate reports breeds in your dog’s genetic background in order of prevalence; a paragraph about each breed as well as a behavior, health and personality summary are included.

A report from DNA Print Genomics includes genotypes, ancestral population results and 15-N population results. Ancestral population results indicate your dog’s relationship to each of the four most basic branches of the canine family tree—wolf-like, hunters, herders and Mastiffs—while 15-N population results are a set of numbers that compare a sample to groups of breed signatures in the database. Each owner is given an ID and password that are used to query the online database for matches to specific breeds.

The Mars Veterinary report presents images of the breeds present in your dog’s ancestry, with the relative size of the image indicating the prevalence of each breed. An appearance, behavior and history section describes characteristics of each identified breed that might be seen in your dog.

As the companies run more tests and add breeds to their databases, the accuracy of the results may improve. It is also possible that even more companies will enter the canine breed ancestry DNA test field. When deciding where your dog’s sample will be submitted, determine what you want to learn and educate yourself about each of the tests. All of the companies agree that working with your veterinarian will ensure that you get the most out of your results. Who knows, choosing the test that best matches your needs could do more than just earn you a victory in the great German Shepherd/Doberman Pinscher debate!

*None of these tests are designed to identify purebred dogs, and the AKC will not accept test results for registration purposes.

Want to read more about dogs and DNA? Click here.

Culture: Science & History
Buffon
The Science and Art of Georges-Louis Leclerc, Comte de Buffon

In setting out to explain everything that was known about the natural world in his 44-volume Histoire Naturelle, Georges-Louis Leclerc, comte de Buffon (1707–1788) reserved a special place for the dog. In fact, he may have been the first naturalist to raise the question of the role of dogs in human evolution: “To conceive the importance of this species in the order of Nature, let us suppose that it never existed. Without the assistance of the dog, how could man have conquered [and] tamed…the other animals. … The training of the dog seems to have been the first art invented by man; and the result of this art was the conquest and peaceable possession of the earth.”

Born in 1707 in Montbard, Burgundy, the son of landed gentry, Buffon was interested in many disciplines; he studied law and mathematics, and was also fascinated with the biological sciences. The first few volumes of Buffon’s groundbreaking work were published in 1749, in the middle of the French Enlightenment, a period considered to “have given birth to the modern world.” Yet it was also a time steeped in church doctrine that provided only dogmatic biblical answers to most questions about biological diversity.

His Histoire Naturelle was an ambitious and tremendously popular project; it was the most widely collected work of its time and reached more readers than even the classics of Voltaire and Rousseau. Replete with Buffon’s insightful theories on everything from the formation of Earth and the planets to crustaceans and rhinoceros, it contained beautifully executed and detailed illustrations (including those of dogs, as shown here). Arguing for a more dynamic and inclusive natural history, Buffon resisted the detailed taxonomic classifications of Linnaeus.

In his foreword to Jacques Roger’s biography, Buffon (1997), L. Pearce Williams writes that “it is no exaggeration to suggest that Buffon’s ideas stimulated much of the scientific work in natural history that culminated in the Darwinian synthesis. Even when he was wrong, as he often was, he was precise enough in his errors to permit others to see beyond his vision.”

In considering the dog, Buffon was fascinated by the many different types of canines. He recognized 30 “fixed varieties,” but acknowledged that there could be even more. He also described 17 “races”—as he called the differences within species—that he attributed to geographic influences such as climate. Into one of these groups he put the “shepherd dog, the Pomeranian, the Siberian, the Lapland and Iceland”—dogs that have “an instinct which induces them to follow and protect flocks”; into another group were “the grey-hound [sic], the large Danish dog and the Irish grey-hound.” Dogs in this latter grouping “are fond of running, and of following horses and carriages … they hunt rather by eye than the nose.”

The next grouping belonged to the “true hunting dogs,” the “hounds, harriers, spaniels, terriers and water-dogs.” Lastly, he grouped the “small Danish dog and the Turkish dog” together, and placed the British “bull-dog” in its own “group,” noting that it was difficult to “preserve” that particular breed in France—he remarked that these dogs “often send forth a disagreeable smell.” In his construction of a canine genealogical tree, he placed the “shepherd dog” at its root. He tried to mate a dog with a wolf, and a dog with a fox, but because his limited experiments were unsuccessful, he concluded that they all were distinct species and that the “dog derives not his origins from the wolf or fox.”

It was with his theory of “degeneration” of species due to climate, and most especially to the climate of the New World, that he had the most long-standing influence outside of the scientific field. In fact, modern pundits have ascribed the fractious Franco-American political relationship to Buffon’s “barkless American dog” theory. Although it was Dutch philosopher Cornelius de Pauw who first claimed that “dogs cease to bark” when brought to America, Buffon picked up on this observation and used it to partially explain the differences in Old and New World species. He thought that the latter were of the “degenerative” variety—weaker, smaller and generally more puny—hence, dogs unable to bark.

Great American thinkers, including Hamilton, Jefferson and Franklin, took umbrage at this, believing that it was meant to extend beyond “natural history” to politics—that this “American degeneracy” was also being applied to their newly formed style of government. In number 11 of the Federalist Papers, Hamilton wrote, “Men admired as profound philosophers have, in direct terms, attributed to her inhabitants a physical superiority, and have gravely asserted that all animals, and with them the human species, degenerate in America—that even dogs cease to bark after having breathed awhile in our atmosphere.”

Jefferson wrote his book Notes on the State of Virginia (1781) to refute Buffon’s theory, and included a “careful analysis of the relative sizes of American and European animals.” Buffon recanted this theory before his death, but old myths die hard. The “barklessness” of our dogs survived well into the last century, when the poet Paul Claudel, serving as the French ambassador to the United States in the 1930s, repeated this fiction.

Though most of Buffon’s theories explaining natural phenomena were, by and large, incorrect, one of the most important contributions he made—as was noted by biographer Jacques Roger—was to “transformed the way of understanding nature.” Buffon’s courageous and innovative approach paved the way for Darwin and other revolutionary thinkers responsible for much of what we know today about the natural world.

ABOUT THE ARTIST
Jacques Eustache de Sève (1742–1788) was the principal artist commissioned by Georges Buffon for his Historie Naturelle. His lovely and lifelike illustrations were complete scenes that included classical landscape backgrounds, which influenced later natural history illustrators. One writer comments, “The illustrations to Buffon’s original edition are exquisitely engraved and exude aristocratic elegance and charm. Whether the animal depicted is a lion or a pig, it is shown as if in a tableau revealed to our curious gaze by the drawing aside of a curtain. The animals do not seem like wild beasts roaming free in their native woods, deserts and mountains, but like actors performing among stage props and painted scenery for the benefit of the lords of creation.” These illustrations were engraved on copper plates and printed on paper made of cotton or linen rag, which contributes to their long-lasting qualities. The original engravings were produced in black ink, and hand-painted with watercolors centuries later.

 

Culture: Science & History
Can DNA Decipher the Mix?
Unraveling the genetic tapestry provides clues to breeds and their mixes

A mongrel dog is like a box of chocolates: You never know what you’re going to get. And therein lies the appeal. What’s more fun than serendipitous unpredictability all bundled up in puppy fur? But when that puppy grows up, we inevitably make assumptions about her ancestry based on how she looks and behaves. Our logic goes like this: “If my pooch is long and low to the ground, and she never barks, she must be a Corgi/Basenji mix.”

But it’s much more complicated. The genes—and there may be hundreds—that work together to make a Corgi look like a short-legged Shepherd may be completely different than those responsible for a Basset Hound’s low-slung carriage. With some exceptions, scientists cannot yet connect genetic dots to specific traits. But they have discovered something tangible that measures some of the differences between breeds: genetic patterns of organization displayed on a scatter graph that answer the question, “What’s the same and what’s different?”

A scatter graph provides a symbolic visualization of DNA, wherein each individual dog contributes one point. The resulting pattern indicates the type and strength of the relationship between individuals. The more the points cluster around each other, the more alike they are.

 

Breakthrough
Until only a few years ago, scientists couldn’t identify the differences in genetic material that might explain profound variations in the Canidae clan. From wolf to West Highland White Terrier—they all looked the same under the microscope. Then, in 2004, Elaine Ostrander and her colleagues at the Washington-based Fred Hutchinson Cancer Research Center published data indicating that as much as 30 percent of the dog’s genetic material accounts for breed variation (Science, May 2004).

In addition to simplifying methods used to find markers for breed-related disease, the researchers identified patterns of “breedness” and tracked the history of breed DNA. At the same time, by following mitochondrial DNA, genetic material passed down from mother to offspring without changing, they traced the breed’s journey.

Depending on how much time is attributed to a generation and how many generations are involved, scientists can estimate how much time has passed. Based on this tracking, it has been suggested that it took 5,000 years to develop and refine a handful of the world’s 350-plus breeds, and about 400 years to create the rest.

Research indicates that four distinct breed groups are ancient: (1) Middle Eastern Saluki and Afghan, (2) Tibetan Terrier and Lhasa Apso, (3) Chinese Chow Chow, Pekingese, Shar-Pei and Shih Tzu; Japanese Akita and Shiba Inu, (4) Arctic Alaskan Malamute, Siberian Husky and Samoyed. Although the 13 breeds look different, they are so closely related that they are represented by a single genetic cluster. It’s likely they all originated from the same stem-parent—proto-breed, if you will—who roamed the Asian continent.

As humans migrated from one place to another, this ubiquitous proto-breed trotted along, bringing with her the ingredients needed to cook up all the breeds we’re familiar with today. Her offspring performed work unique to each geographical region, such as hunting, hauling or guarding. Isolated and mating only with each other, “accidental” breed types exhibiting consistent shape, color and behavior emerged.

No matter what historians might claim—scent hound to sight hound, bird dog to bad dog—evidence produced through genetic research indicates that all remaining breeds have been concocted in the last 400 years. Although closely related to one another, they can be identified as distinct based on the way their DNA separates.

How They Do It
Sue DeNise, vice president of genomic research at MMI Genomics Inc., which developed the Canine Heritage Breed Test specifically for mixed-breed analysis, talked to us about how her company analyzes canine DNA. “We’ve been doing testing for AKC parentage verification for a long time,” she notes. “We initially started working in the cattle business, looking for genetic markers in order to trace what was important to cattle breeders. Out of that whole-genome association study, we had purebred and crossbred cattle, so we asked, ‘What can the markers tell us about underlying traits in breeds of cattle?’” Their discovery paved the way for the companion animal program, which was modeled on what they learned with cattle.

“We look at ’breedness‘ among dogs. Our canine database is built with 10,000 samples of 108 breeds. We ran 400 markers to identify the best markers for a ’breedness‘ test against 38 breeds. We created a panel of 96 pieces of DNA that split dogs into their identified pure breed. In our preliminary test, we found that individual purebred dogs cluster with other purebreds.” Initially, MMI chose 38 AKC registered breeds from their database, selected for their popularity based on number of registrations. Recently, as DeNise notes, they increased the number to 108 breeds. This jump in breed recognition required testing thousands of markers to identify the just over 300 markers that characterize these 108 breeds.

Constructing Breeds
Like all species, domestic dogs are on an evolutionary journey, starting at wolf and going somewhere yet to be determined. We tinker with evolution, but might be surprised to find out we don’t control it. Our concept of a breed—that individuals within the breed look alike—is nothing more than a snapshot of the DNA time line, taken while we’re doing the tinkering.

Breeds are created a number of ways. In simple terms, when breeders interfere with natural reproduction and rigorously select for traits favored by humans, specialized breeds like Retrievers, Spaniels, Hounds and Terriers are the result. Saving spontaneous mutations in a litter of dogs, repeating the breeding to get more of the same mutation, and breeding those dogs back to one another has resulted in the English Bulldog, Chinese Crested and Inca Hairless. More recent breeds, such as the Airedale, Australian Cattle Dog and Doberman, are the result of crossing older breeds to make new ones.

When kennel clubs closed gene pools in the late 19th century to suspend change in registered dogs, breeds drifted toward a more uniform stereotype. Until the early 1800s, an assortment of dogs with similar talents who could produce somewhat similar offspring were awarded the right be called a breed. Breeds evolved, flourished and disappeared when jobs were eliminated. Tumblers, who mesmerized prey by “winding their bodies about circularly, and then fiercely and violently venturing on the beast,” disappeared when guns came into widespread use. Turnspit dogs, who made a living running on a wheel to turn meat so it would cook evenly, received their pink slips when technology improved cooking methods.

By and large, Victorian society was not so pragmatic; sentimentality and commercial opportunity were catalysts for saving unemployed breeds from their inevitable demise. As a result, many Terrier breeds went from killing varmints in the barnyard to killing time in the Victorian parlor in less than a decade.

Whereas previously, a breed was a regional product maintained and preserved by a small community of knowledgeable people, commercial interest in the well-bred pet dog initiated a shift in breeding practices during the Victorian era. The old-money kennels operated as a pastime by the wealthy gave way to a large number of small, commercially operated kennels run by entrepreneurs of modest means and experience.

Germane to this tale is that, according to the unwritten rules governing canine physiology, anatomy and behavior go hand in hand. One cannot be changed without affecting the other. Victorian enthusiasts who were busily adding aesthetic traits to utilitarian breeds were creating not only subtle variations in type, but in many cases, modifications in behavior as well. As utilitarian breeds went from working hard to hardly working, many exhibited new physical and behavioral characteristics that were compatible with their augmented duties as companion animals. Breeders claimed the “sub-breeds” as their own, made up new names and registered each one.

However, no matter how they’re sliced and diced, reducing and suppressing genes so they aren’t expressed doesn’t mean they’ve been eliminated. They’re still lurking and, depending on the method used to analyze the DNA, the lurkers often show up in the results.

Deconstructing Breeds
The problematic aspect of analyzing mongrel DNA is that breeds were not all created at the same time. As DeNise explains, “As new breeds are developed, they may not appear as uniform as older breeds. When older breeds are crossed to create a new breed, there is some period of time before the new breed develops a unique DNA pattern of its own. In these cases, the more ancient breed sometimes appears in the new breed. The number of generations required to have a uniquely identified breed created from crossing of older breeds depends on the number of breeding animals in the new line, the severity with which the breed owners apply the standard, and the amount of introgressing [inbreeding, or breeding immediate relatives; line breeding, breeding close relatives; and backcrossing, breeding sibling to parent] allowed by the registration agency.”

Most people assume all mixed-breed dogs had a purebred ancestor at some time in their recent heritage. But in fact, this is not necessarily the case. When you run a mongrel’s DNA through a computer program, the algorithms attempt to group breeds together on a scatter chart. If the heritage of the dog is such that it is not in MMI’s database of 108 breeds, the program tries to find varieties that are most alike. Because at least one or two of the handful of ancient breeds are in every modern dog, sometimes the program will identify an ancient breed in the mix. “In the report we send to the client, we use the terms ‘primary,’ meaning the majority of the DNA matches a breed; ‘secondary,’ meaning less than the majority of the DNA but a strong influence nonetheless; and ‘in the mix,’ meaning the least amount of influence,” DeNise notes. That’s how you might get an obscure breed in the report. For instance, a 35-pound mongrel with a tablespoon of Husky and a teaspoon of Border Collie may also have a dash of Borzoi, because before gene pools were closed a century ago, Huskies were crossed with coursing hounds to add speed.

Don’t Judge a Pup by Her Cover
As MMI Genomics states on their certificates, “Your dog’s visual appearance may vary from the listed breed(s) due to the inherent randomness of phenotypic expression in every individual.” What this means is that you may look nothing like your parents, but you have Grandma’s great legs and Great Uncle Harry’s turned-up nose. All in all, though, no matter how genes are mixed and matched, your family members resemble one another. However, if Grandma was an Afghan Hound and Great Uncle Harry was a Pug, “random phenotypic expression” can be pretty extreme.

Researchers are intrigued by data that suggest expressed traits are somehow turned “on” and “off” by other genetic components, thus causing the wide variations in canine form and behavior. For instance, it’s possible that many breeds have the genetic potential for a black tongue, but only a few breeds have the molecular mechanism to switch that color on. So that black-tongued mutt may not have any Chow in the mix after all.

On the other hand, the results may show that a quintessential Heinz 57 has the genetic makeup of a single breed and it could be one she looks nothing like.

DeNise explains it this way: “In a population of any breed, there are dogs that are carriers but don’t exhibit phenotype [observable characteristics]. If you reduce the size of breeding population—creating what we call a bottleneck—you start increasing the frequency of deleterious traits, like dwarfism or white coat. If we looked at the DNA of, for instance, a group of white mini-German Shepherds, they would probably cluster with German Shepherds. After they’ve intermated for five to six generations, we may not come up with that. They would cluster with each other. If breeders were changing allele frequencies quickly, you could do it very fast.

“There are always contradictions that make you say, ‘Huh, that’s really weird.’ One odd thing that happens is due to some sort of random assortment of genes in mixed-breed dogs. The algorithm may identify a breed that is not consistent with the physical appearance of the dog. We sometimes get an indication of this when the certificate is printed with the picture of the dog provided by the owner, and the certificate is reviewed by our customer service department prior to mailing it to the pet owner.”

A 90-pound, wiry-haired mongrel who swims, chases balls and makes goo-goo eyes like a Golden Retriever and whose only pedigreed relative is a very distant Chihuahua confounds the process, but says a whole lot about the complexity of canine genetics and why some scientists devote their careers to studying canine evolution. Extreme variation in anatomy and behavior is unique to the domestic dog. If humans were an equally anomalous species, we’d weigh between 20 and 650 pounds and range in height from three to 10 feet. In dogs, adaptations change with such speed that scientists suspect there may be a clue in the canine genome that could reveal how evolution works.

Sorting It Out
Before they launched the project, MMI tested DNA from a street dog rescued from a Thai village. You’d think there would be no clusters of any kind, but the computer identified Chow and Akita in the mix. This isn’t surprising, because the free-living common village cur who populates most of the developing world may be the closest living relative to the original proto-breed. Findings suggest that Thai pooch stores a sizable chunk of the original genetic blueprint of every single living dog in her DNA. The question is, how much?

MMI can’t as yet define the percentage of “breedness” in mixed-breed dogs. One reason is that some breeds cluster loose and others tight. Why this happens isn’t clearly understood. German Shepherds, Standard Poodles and Collies cluster tight. Miniature Poodles cluster tight, but Toy Poodles cluster loose. Within their breeds, Labrador Retrievers and Beagles often cluster as two different groups. According to DeNise, “Labs from the United Kennel Club that are bred specifically for hunting and AKC Labs do not necessarily cluster as one breed. And AKC Beagles and Beagles bred specifically for research don’t cluster together either.”

She adds, “In my opinion, it’s possible that a population that increases rapidly doesn’t cluster as well as those populations that have remained static. This is because, as you increase a population to accommodate breed popularity, people breed everything, including animals that may not exhibit all the physical characteristics that are desirable.”

And even when dogs look alike, they can display behavioral differences. As DeNise notes, “We understand so little about how behaviors are coded. Many behaviors are learned, but there are probably multiple genes that are responsible for herding, birding, heeling—these kind of hard-wired behaviors.”

Scientists are eager to tease out genetic connections to breed-associated motor patterns. When wolves hunt, they display these behaviors sequentially: orient > eye > stalk > chase > grab-bite > kill-bite > eat. Artificial selection, however, extracts and segregates these patterns in incomplete sequences. In certain breeds, individuals perform the abbreviated motor pattern repeatedly. A Pointer who stops dead in her tracks and stands stock still with her front leg held rigid in mid-stride to indicate the presence and position of game is the lofty goal of bird-dog breeders. To wolves, it’s just a good meal interrupted.

Combinations of canine anatomy and behavior push and pull one another along in a rhythm of interconnected patterns in relationships that may not be as random as they appear. Like principal components of an automobile in which the size of the engine and the weight of the body directly affect efficiency, it appears that dogs, too, have integral parts wherein one component is proportionate to the other.

Researchers don’t fully understand the relationship, but they are making headway. As reported in Genetics (June 2008), a team of scientists identified a few single genes that regulate systems controlling skull shape, weight, fur length, age span and behavior. Because mutts are combinations of DNA from different breeds, they may hold the answer to how the genes influence multiple traits.

Scientists suspect that many evolutionary secrets are hidden in the dog genome. For dog lovers, deconstructing Molly or Max’s mixed-breed heritage is an interesting intellectual mystery to be discussed at cocktail parties or the dog park. For scientists, their genetic material is nothing less than an instruction manual for species building. Whereas populations evolve over the course of millennia through the process of natural selection, dogs can change so rapidly and abruptly that they represent evolution at hyperspeed. How it happens remains a puzzle. Now scientists are looking to mutts to find the missing piece.

 

 

News: Guest Posts
Very Big Fleas
New evidence of ancient bloodsuckers

Flea problems got you down? Well, count your lucky stars that you’re not raising a pack of pet Brachiosaurus. Recently, paleontologists in China discovered fossil evidence of Jurassic fleas that were as long as a thumbnail with sharp “mouth parts” all the better to dig into dinosaurs’ tough reptilian skin. Shudder.

News: Karen B. London
Genetic Control of Canine Appearance
A few genes make all the difference

My relationship with dogs is sometimes a bit split. One side of things is that I love them, for all the reasons everybody reading this understands so well. Another side of my relationship with dogs is my fascination with them—a true scientific interest, based on some of their extraordinary characteristics. And research about their genetics has continued to add to their appeal as creatures worthy of great attention, even beyond the fact that they are so lovable.

From the diversity of forms seen in the domestic dog, it’s easy to come to the conclusion that their genetics are unusual. Though other domestic animals including chickens, horses, cows, sheep and cats have many different breeds, dogs alone have the amount of physical variation that is represented by Great Danes, Dachshunds, Pugs and Borzois. Animal lovers are generally interested in that fact, but all scientists ought to be astounded by it, and I most definitely am.

The selective breeding that has led to the range of forms in this species is a fascinating genetics experiment. Geneticists are grateful to the “field work” done by countless breeders over many generations because the dogs that have resulted provide a way to understand things that can’t be learned elsewhere.

One of the most fascinating recent discoveries that makes use of the variation in dogs is that it’s only a few genes that are responsible for the huge range of differences in the appearance of different breeds of dogs. The incredible variation in dog size, fur type, length and color, ear shape and position, and shape of the nose is controlled by just a few dozen gene regions.

In other species, the genetic control of traits such as size and shape is much more complex. For comparison, human height is controlled by around 200 gene regions. Until it was investigated, researchers assumed that underlying the incredible diversity of canine appearances was a corresponding genetic diversity, but it’s just not so. The more we learn about dogs, the more fascinating they become.

Culture: Stories & Lit
Anthrozoology Books Explore the Science and History of Dog-Human Bond

Scientists have only recently caught on that canines are not just a fertile subject for their particular specialties — psychology, anthropology, zoology, ethology and more — but also a topic that the publishing world seems eager to promote.

This trend has been a long time developing. Nobel Prize–winner and ethology’s co-founder, Konrad Lorenz, wrote Man Meets Dog (1950), breaking ground that lay dormant until anthropologist Elizabeth Marshall Thomas’s bestseller, The Hidden Life of Dogs (1993), reintroduced the genre of dog studies to the non-scientist reader. A few years later, journalist Mark Derr followed up with Dog’s Best Friend (1997), a book that grew out of his Atlantic Monthly investigative piece about the AKC and the dog-show world. Another dry spell was finally broken by psychology professor Alexandra Horowitz’s Inside of a Dog (2009), which garnered an extraordinary amount of well-earned praise. At long last, it seems that the (overly) popular dog-memoir craze has given way to illuminating and well-researched books that explore the science behind our favorite species, written for the general public.

For example, in the May issue of Bark, we reviewed Dog Sense, a fascinating book by British anthrozoologist John Bradshaw, in which the author provides a compendium of current research (both his own and others’) into dogs’ origins and behavior. More specifically, he details their evolution from a wolf-like ancestor into proto-dogs and then the first domesticated species; he also investigates how this very long-term relationship has affected both canines and humans. He goes on to clearly explain how today’s dogs differ behaviorally and culturally from wolves, and why the dominance/ pack paradigm put forth by many trainers (including Cesar Millan) is not only the wrong way to understand dogs but has also done them a great disservice. It makes for engrossing and thought-provoking reading.

Paleoanthropologist Pat Shipman takes a similar synoptic approach in her engaging new book, The Animal Connection: A New Perspective on What Makes Us Human, and adds valuable insights into the dog’s evolutionary story. She combs through research in her own field as well as in archeology to test her hypothesis that animals (dogs among them) have shaped our species’ evolution. As she says, “I believe that a defining trait of the human species has been a connection with animals…. Defining traits are what make humans human … and they are partially or wholly encoded in our genes.” She does a rigorous investigation — every bit as compelling as a forensic TV drama — into the three big advances that contributed to our modernity: tool-making, language and symbolic behavior, and the domestication of other species to support this position.

In the chapter, “The Wolf at the Door,” Shipman suggests how domestication might have happened. As importantly, she refutes other theorists, such as Raymond Coppinger and his “protodog- as-village-pests” model. She writes about Belgian researcher Mietje Germonpré, whose work recently dated a proto-dog fossil skull to 31,680 BP — proving that dogs were domesticated long before humans congregated in settlements. (It was an amazing 20,000 years before the next species, the goat, was domesticated.) Shipman questions why so few representations of wolves/dogs (as well as human figures) appear in prehistoric art, and incorporates anthropologist Anne Pike-Tay’s suggestion that if domesticated dogs were helping us hunt, they were “perhaps placed in a completely different symbolic category from other animals,” adding, “dogs might have been put into the human family category as an extension of the hunter.” All of which attests to the fact that dogs have been a part of the human family since our own prehistory — an extremely long time.

All of these books, the classics and the current crop, should be read by dog lovers. Not only do they contribute to our understanding of our first friends, they also have the potential to improve dogs’ welfare by educating us as to what we can and can’t expect from them. We owe it to dogs to learn more so this age-old relationship can grow even stronger. Here’s hoping this trend continues and more groundbreaking books are on the way.

Culture: Reviews
Dog Inc.: The Uncanny Inside Story of Cloning Man’s Best Friend
Avery Publishing, 320 pp., 2010; $26.00

After the birth of Snuppy, the world’s first cloned dog, a handful of biotech entrepreneurs envisioned a thriving business that would provide grieving dog lovers with genetically identical clones of their deceased pets. In Dog Inc., Pulitzer Prize-winning investigative journalist John Woestendiek exposes the grave folly behind those science-fiction dreams.

Woestendiek travels between the United States and South Korea, following the companies looking to cash in on cloning technology, and their clients, who hope cloning really will approximate resurrection.

Although much of the book focuses on the salacious story of Bernann McKinney, a woman obsessed with cloning her Pit Bull, the strength of Dog Inc. is in Woestendiek’s ability to lay out the science and laboratory politics in a way that’s both accessible and engaging. Readers will understand the X-inactivation process that made the first cloned cat so physically distinct from her progenitor — and, consequently, such a public relations failure — as well as the allegations of scientific fraud levied against Woo Suk Hwang, one of the pioneers of canine cloning.

Woestendiek never outright condemns canine cloning, but the details leave little question as to where he falls in the debate. He shines light on the poor treatment of the laboratory dogs used in cloning, the cloned puppies who do not survive the process and the heartbreaking fate of Snuppy himself. As for the actual clones, Dog Inc. tracks kittens, puppies and even a bull cloned at great financial and biological cost, only to prove physically and behaviorally distinct from their genetic parents.

The book serves as a valuable reminder that, like people, our pets are far more than the sum of their DNA.

Culture: DogPatch
Q&A with Dog Sense Author John Bradshaw
Making sense of dogs

What is an anthrozoologist, anyway? Turns out it’s someone who studies human-animal interactions, and John Bradshaw, who directs the world-renowned Anthrozoology Institute based at the UK’s University of Bristol (and founded it at the University of Southampton), is pre-eminent among them. For more than a quarter of a century, he’s investigated the behavior of dogs and their people, and his findings have been widely published. In Dog Sense — his best-selling, recently released book — he expands upon his belief that “the future of the dog does not lie simply with the blunt instruments of legislation and regulation, but with better public understanding of what dogs actually are, their needs and wants.” Recently, Bradshaw shared his thoughts on evolution, training (debunking the myth behind the “dog as wolf” model), changes in breeding practices in the UK and what lies behind dogs’ attraction and attachment to us, among other intriguing ideas.

Bark: Why do you think that a proto-dog — a transition from wolf to dog — evolved?

John Bradshaw: My theory — and I have nothing to back it up — is that something happened in the brains of certain wolves that made dual socialization possible. Humans developed a propensity to take in pets, and then these particular wolves came along — these would be the protodogs. They would have looked exactly like wolves. This was not an intervention on our part, but rather, a very different cultural environment.
A key difference between dogs and wolves is not their appearance but rather, how they behave. Dogs have the capacity to socialize to both species, ours and their own, and the unique ability to continue functioning as members of their own species while simultaneously establishing and maintaining relationships with ours.

B: Most researchers refer to domestication as a one-way street. Didn’t other species, including the wolf and proto-dog, also have an effect on our own evolution?

JB: Domestication was a long and complex process; speculatively, I would [say] that there were several failed attempts. Researchers who are studying human evolution and the human brain pretty much say that our own evolution — at the genetic level — wasn’t influenced by dogs. But, of course, our culture has been profoundly influenced by them.
Dogs were, for a long time, a crucial part of our technology and their domestication marked a technological innovation that also provided the blueprint for the domestication of other animals; if we were able to domesticate dogs, why not pigs, sheep, cattle, goats? So if you are talking about evolution in the general sense of where humans are today, what we think about and how we see the world, then, yes, dogs dramatically affected that evolution. If you are talking about dogs affecting genetic evolution, we haven’t discovered that yet. I’m not saying we won’t, but we aren’t there yet.

B: Do you think it’s possible that we hunted together, or perhaps learned or honed our own skills by watching wolves hunt?

JB: I don’t think we were hunting partners, to begin with, but one of the versions of human evolution that I strongly subscribe to comes from Steven Mithen, a cognitive archaeologist and professor of early prehistory, who studies the evolution of the human mind and why we are different from the Neanderthal — why they died out and we didn’t. One of the key [dissimilarities] he points to is our ancestors’ ability to think like animals. They could put themselves in the place of an animal — that they, in fact, had a connection to the animals. So we would be able to think, “If I were a wolf, what would I be doing?” or, “If I were a deer, what would I do now?”

B: If scientists have concluded that wolf behavior is different from that of dogs, why do people still consider the lupomorph (wolf pack) model as a determinant of canine behavior?

JB: They have a good excuse, which is that in terms of their DNA, dogs and wolves are so similar. However, that doesn’t mean there is similarity in their behaviors.
Confusion about how wolves actually behave comes from observations of wolves artificially grouped in zoos. A natural pack is based on a family, but those confined in zoos and so forth are not family units. So in a zoo their behavior looks like it is one of dominance hierarchy based on aggression. The whole basis of wolf behavior [in that context] is not natural. It’s like comparing all human behavior to the behavior of humans in refugee camps. In that kind of group, behavior is distorted.
The second reason is that proto-dogs, the wolves who became domesticated, were different than other wolves. The animal who was the common ancestor of wolves and protodogs has been extinct for at least 15,000 years. Wolves in the wild are getting wilder and wilder for at least 15,000 years, probably longer.
Recent interpretations of wolf behavior have emphasized cohesive, rather than aggressive, behavior as being essential to the stability of a pack. Wolves in different packs try to avoid one another, but dogs are extraordinarily outgoing. Dogs’ sociability is even more remarkable when compared to that of their ancestors.

B: If the wolf model isn’t appropriate, what is?

JB: The behavior of feral, or village, dogs in Italy, Russia and India has been studied recently, and results show that those dogs are much closer to the ancestors of pet dogs than wolves are. These are urban feral dogs, high-density dogs, dogs in large groups. Earlier studies [of feral dogs] were conducted in environments in which the dogs were being persecuted and are like the early captive-wolf studies: not reliable.
Research recently conducted in West Bengal (where feral dogs are more tolerated by the people) has found that feral dogs are a lot more tolerant of one another than wolves are. Family bonds form, but with less correlation. They do not hunt together, but rather, forage singly, and, unlike in a wolf pack, more than one female in a social group will breed at the same time. They aren’t a pack in the wolf sense; their “pack” structure is very loose and rarely involves cooperative behavior, either in raising young or obtaining food.
The studies of West Bengal feral dogs don’t offer the slightest shred of evidence that they are constantly motivated to assume leadership of the pack within which they live, as the old-fashioned wolf-pack theory would have it.

B: You write that there is little evidence that hierarchy is a particular fixation of dogs — that dogs do not want to dominate us — but so many trainers (including Cesar Millan, as you note in the book) and others use this construct to explain dog behavior. Why is this wrong and what are its implications?

JB: Part of the problem is that confrontation makes good television, and attracts programmers, but having a confrontation in your living room with your own dog isn’t the best way to train a dog. The more effective way is to use reward-based training, which can be (by television standards) incredibly dull, since it may take hours or sometimes weeks. My colleagues and I are appalled by the popularity of this style of confrontational dog training. I don’t know what the situation is in your country, but in the UK, we have a new Animal Welfare Act, and that kind of training goes against its recommendations. The law reads, “All dogs should be trained to behave well, ideally from a very young age. Only use positive reward-based training. Avoid harsh, potentially painful or frightening training methods.”
There is little evidence that hierarchy is a particular fixation of dogs, either in their relationship with other dogs or in those with their owners.
And if some trainers believe that dogs only perceive us as if we were other dogs (or wolves), there is no logical basis for assuming that dogs [instinctively] want to control us. Domestication should have favored exactly the opposite: dogs who passionately want us to control them.

B: Have you seen any changes in breeding practices in the UK as a result of the BBC’s “Pedigree Dogs Exposed” documentary?

JB: The genetic isolation of breeds has brought about a dramatic change in the canine gene pool. Three inquiries have been commissioned: one by the Royal Society for the Prevention of Cruelty to Animals, another by the government and a third by the Kennel Club itself, but there is still a great deal to be done. There are problems implementing the studies’ conclusions because the KC, like the AKC, is a federal structure made up of individual breed clubs. The federation has no power to tell the member breed clubs what to do.
There is also an unfortunate loophole in the UK legislation, in a macabre sort of way: the law doesn’t apply to fetuses so if there is a hereditary defect, it can be legal!
Top breeders, those who show their dogs, practice selective breeding to meet the latest interpretation of the breed standard, which is based on the appearance of the dog. The whole basis of judging rests on how a dog looks and behaves in the show ring.
Some of breeds’ gene pools are too small, and the answer has to be to amalgamate breeds to increase genetic variation. A group of people in Australia are taking on the breeding of pet-quality dogs, [selecting for] calm personality, trainability, freedom from inheritable disease and discomfort, people-focused and so forth. Dr. Paul McGreevy and Pauline Bennett are part of this group. Genetics can only go so far, though. You have to mold a dog’s personality — it can’t be done through genetics alone.

B: Many people use puppy testing to predict a dog’s adult character. Do you feel this is valid?

JB: Dogs are born to become friendly toward people, a process that starts in about the third week of their life and goes on for several months. This process of socialization is well charted. At 16 weeks, the window of socialization to people begins to close, though it stays open a bit longer for socialization to other dogs.
Young puppies try out different behavioral approaches; they change from one day to the next. It is more important to look at the litter’s environment — how is the female kept, for example? Puppy tests carried out at seven or eight weeks of age are being conducted when a puppy’s behavior is actually most malleable. Numerous scientific studies have failed to find any validity in puppy testing as a predicator of future character. The only personality trait that seems to be resistant to change after seven weeks is extreme fearfulness.

B: You write that dogs have been so heavily selected to form strong attachments to humans that many suffer from separation anxiety — up to 50 percent of Labs bred in the UK, for instance. On what is this finding based?

JB: It comes from my own research and that of others. We concluded that many dogs experience this anxiety at some time in their lifetime. In one longitudinal study, we followed puppies, 40 in all, litters of Labradors and Border Collies, from eight weeks to 18 months old. Over 50 percent of the Labs and almost half of the Collies showed some kind of separation distress. Subsequent studies, during which we filmed dogs left alone, showed that self-reporting by owners underestimates the scope of the problem.
We work closely with rehoming charities, instructing them on prevention and ways to train dogs so they won’t suffer when left alone. The key thing is to get new owners to train the dog to understand that they are coming back.
This is not a disorder at all, but rather, a perfectly natural behavior. We have selected dogs to be highly dependent on us. Research has shown that just a few minutes of friendly attention from one person on two consecutive days is enough to make some dogs in shelters desperate to stay with that person. Their attachment to humans is that strong.

B: One of the most controversial positions you take is that being in a shelter may damage a dog. Was consideration given to contributing factors such as the length of time spent in a shelter, the condition of the facility, the interactions a dog has with other dogs and humans there, and the dog’s personality and history?

JB: We want to understand what is going on inside these dogs, and I am not in any way blaming rescuers or shelters. Dogs who have been attached to a family may suddenly wind up in a shelter for a variety of reasons: family breakup, job loss or the dog’s behavioral problems. Dogs will be very upset by this and when they arrive in a shelter, their cortisol level [a stress-related hormone] goes sky high. We know this because when we’ve taken urine samples, we’ve had to dilute the urine to even get a measurement — it was that high. They don’t have the resources to cope and go into hyperdrive, desperate to please people. As a result, in a shelter setting, dogs actually can be easily trained.
As I mentioned, attachment can happen quickly in shelters. Of course, when dogs are unhappy, they need to be appropriately cared for, but we find that it’s important to rotate their caregivers so they don’t form an attachment to any one person.
It is also important to assess dogs for separation anxiety, predict the behavior, and advise [shelter staff and prospective adopters] on how to train them to be left alone. That is one of the most important things you can do to ensure the welfare of the dog [in terms of his or her eventual placement] in a new home.

B: Dogs clearly love us, and demonstrate that in many ways, but is this what motivates them to obey us and follow our lead?

JB: Human contact has a high-level reward value for dogs; simple attention from us is rewarding. And if that attention comes while playing with them, it can be a double reward. You can train a dog with a tennis ball, but while the game is important, it is not the only thing. The real treat is the interaction. Withdraw your attention, ignore the dog, and the dog will find this withdrawal of attention aversive.

News: Karen B. London
Dogs Vary in Size Within Breeds
How big is the range?

Last weekend, there was a chocolate Lab at the athletic fields where my husband and I were playing flag football with some other people, including his guardian. Both my children had a ball running around with Porter on the sidelines. He was very sweet and well trained. He played Frisbee, chased some of the adults around if they enticed him to do so, and got off the field and sat when asked to do so. He was energetic, but not overly aroused, let everybody pet him, and was generally a credit to his breed.

  He was also enormous. He weighs 105 pounds, and while nobody would describe him as svelte, he wasn’t overly fat as we regrettably know so many dogs in this country are. It’s hard to say, but I would guess that his perfect weight would be somewhere in the low 90s, which is still a large Lab. He was broadly built and unusually tall for his breed. His loping style of running made me wonder whether he had any Great Dane in him, but I was told he’s all Lab.   Lately, I have seen quite a few Labs who are pretty large, and yet I’ve also seen ones who are so small I suspect people often think they are adolescents who are yet to reach full height, event though they are 3-years-old, 5-years-old, or more—certainly full grown. I’ve seen dogs of other breeds who seem far from typical in size, including a Brittany who is 5 inches taller than all his littermates and an Airedale Terrier who was much closer in size to an average Irish Terrier.   I know that despite breed standards, what’s popular in terms of size varies over time. And sometimes, for whatever reason, dogs are born who don’t match the size typical in their lines. Coming from a family with women who range in height from 4’9” to 5’11”, I am very interested in diversity in size among relations.   Do you have a dog who is either unusually large or unusually small for the breed?

 

Pages