Now recognized as a stable family pet, the labradoodle was invented in the 1990s to be a low-allergen guide dog. The recent origin of the breed and the portmanteau name make it quite obvious that Labradors and Poodles mixed together in the creation of the Labradoodle. But what about the other 400 dog breeds? How does a wolf become a Pomeranian?
The origin of modern dogs dates back tens of thousands of years (between 20,000 and 40,000) when humans domesticated an ancient relative of today’s wolves. People have been carrying out deliberate and selective breeding ever since, initially creating dogs to specialize in herding, hunting and guarding.
Then came the explosion of the Victorian race. The mid-19th century saw a period of intense innovation and codification in dog breeding, giving rise not only to a diversity of breeds, but to the very concept of “breed”. During this boom, disparate dog bloodlines were deliberately crossed to enhance favorable traits or dilute undesirable ones. Crossbreeding was also done for the express purpose of creating novel breeds, selecting for aesthetic characteristics.
This created a messy and intertwined relationship between the different types of dogs, with the details of a breed’s origin sometimes recorded only in oral history.
It wasn’t until a landmark genetic study was published in 2017 that we got a clearer picture of how all of these breeds are related to each other.
Researchers at the US National Human Genome Research Institute analyzed the DNA of 161 breeds to create a family tree of dog breeds. Groups of trees breed in categories based on their shared history. These groups, known as clades, reflect the fact that for much of their domestication history, dogs were only known for the type of service they provided to humanity. Hunting dogs are a family that includes retrievers and setters, herding dogs contain shepherds and sheepdogs.
Dr. Elaine Ostrander is the chief of cancer genetics and comparative genomics at the institute and was the supervising investigator for the 2017 study, as part of NHGRI’s canine genome project.
“What we wanted to know was, how are dog breeds related to each other?” she said.
“We know that most breeds have only been around since Victorian times. There were fanciers in Europe who wanted to create breeds that had a particular appearance or had a particular ability or personality.”
Many of the relationships make some intuitive sense, he said.
“One of the things that is important is the geographic location, where the breeds were developed,” he said.
“Certainly function was also important, and there is certainly a relationship between dogs with the same appearance, such as miniature and standard schnauzers.
“But there are always surprises, things that we may not expect.”
The study also presented analyzes revealing the shadows of crossbreeding concealment in modern “purebred” dogs.
While the genomes of all dogs are 100% canine DNA, a small amount of the genome varies between breeds. These parts are responsible for the impressive spectrum of variation in size, shape and behavior of domestic dogs. The researchers sequenced dog genomes at thousands of these variable sites. When the blocks of them are identical in two different races, this indicates a historical interbreeding between them.
These new results confirmed the documented histories of some breeds. Heidi Parker, lead researcher on the study and also a geneticist at NHGRI, said the results also showed evidence of interbreeding that was undocumented or unexpected.
“We found that the German shepherd was quite Italian,” he said. “I don’t know if we know what the history of the German shepherd really is, other than he is one of the breeds that comes up with the most crosses of various things.”
Here we have used the data from the genetic study to visualize the relationship between a single breed and all other breeds they examined (where the relationship was above a certain threshold – see notes below for more details):
In this example, you can see that the German Shepherd shares a greater amount of DNA with the Cane Paratore, Berger Picard, and Chinook. It is important to note that these graphs do not indicate the direction of the crossbreeding, only that two breeds are more or less related.
“We don’t know the directionality, it just tells us that there has been mixing and matching between races,” Ostrander said.
In some cases, stories of much older races could be confirmed. A legendary beast, the original Irish Wolfhound, had not been seen for almost 100 years and is presumed extinct. In the 1860s, George Augustus Graham set out to recreate it from existing dog bloodlines, starting with the Scottish Deerhound and spraying on some Great Danes to increase size.
The results for the pug, originally from China, were surprising. Breeders have sprinkled a sprinkle of pug genes on a wide variety of breeds around the world, presumably to make them smaller.
Here you can select any breed included in the study to see the relationship with other breeds, or try one of the groups to see a bigger picture of the connections between the breeds.
One thing missing from this review is the so-called “designer breeds” such as goldendoodle or groodle, cavoodle, and various other -oodles.
The reason for this is, according to Parker, that most of these dogs are not an ongoing breed.
“Most of those races, almost all of them, are simply created as unique. But they don’t continue,” he said. “The only group that’s really doing that is the labradoodles, the Australian labradoodle club.”
The NHGRI Canine Genome Team has specifically investigated the Labradoodle, showing that genetically it is more of a Poodle than a Labrador.
Some dogs in the study, such as the dachshund or the gray wolf, had no links to other breeds. Parker said there are a few possible explanations for this.
“The exchange we identified in the document was about 200 years old or less. A couple of breeds, like the dachshund and the Dalmatian, don’t show sharing stripes at that age point,” he said.
“This could mean that these races were established in their current form before that time and no one has seen fit to play with that form. It’s also possible that we just don’t have the right races in the dataset to see other additions.
“That is one of the reasons why we are still adding more breeds and especially regional breeds to our tree, to fill in the missing pieces.”
As for the future of the dog genome project, Ostrander says they’re doing the same analysis across breeds, using whole genomes for comparison.
“One of the questions we’re dying to answer is: what are the differences? What do you see that you didn’t see before at this much higher resolution level?
- The Dog Genome Project is interested in collecting more samples of interesting or exotic dog breeds. You can email email@example.com to see if your sample might be useful in future research.
Notes and methods
The groups used in the figures are the 23 clades provided by the analysis by Ostrander et al, with races without a clade grouped under “other”.
The colors are primarily to indicate whether two dogs are in different clades, rather than to identify the specific clades, as it is very difficult to make a categorical color key work with 23 colors.
The relatedness index simply uses a scale from 1 to 100 based on matching the size of the smallest base pair to matching the size of the largest base pair. Only matches of more than 250,000 base pairs are included as in the original article.
This article was modified on October 26, 2020 to clarify that the dog breeding boom occurred in the 19th century, not the 18th century.