Home DNA Testing for Dogs Leads to Discovery of Genetics for Blue Eyes in Huskies

Many of us have ordered DNA testing kits for ourselves to learn about our ancestry.  But the boom in at-home testing is also spreading to our dogs.

An analysis of the home DNA tests of over 6,000 dogs (combined with photos and surveys from their owners) has led to the identification of a gene duplication on canine chromosome 18 that causes blue eyes in Siberian Huskies.

Duplication of a gene known as ALX4 (which plays a role in eye development) causes two blue eyes or one blue/one brown eye in both Huskies and non-merle Australian Shepherds.

A report on the study on the Science Daily website notes that the growing field of consumer genomics will lead to increased knowledge about our dogs, as well as ourselves.

You can read the full text of the research article HERE.

 

DNA Study Reveals What Happened to the Native Dogs of the Americas

A new study on canine genetics has been getting a lot of attention recently.  Do dogs living in modern North and South America retain the genes of the ancient dogs that accompanied the first Americans who came from Asia thousands of years ago?

A genetic study of the remains of ancient American dogs reveals that they were descended from the ancient dogs of Siberia (somewhat like today’s Arctic dogs such as Huskies and Malamutes) and not the native American wolf population.

These original dogs almost completely vanished after the arrival of European immigrants and their dogs in North and South America.  Only a tiny fragment of their genetic code lives on in modern American dogs…and you may be surprised to find out what it is.

Researchers have discovered that the closest surviving genetic link between these ancient dogs and modern dogs is the canine transmissible venereal tumor, which is a contagious cancer clone that can be traced to one individual dog that lived between 6,000 and 8,000 years ago!

You can learn more about this fascinating topic HERE.

 

Domestic Dogs Leave Genetic Pawprint on Wolves

We all know that our dogs are descended from wolves, but did you know that through continued interaction, domestic dogs have left a mark on the wild wolf population?

A recent international study of Eurasian grey wolves has found that 60% of these wolves carry some domestic dog DNA, proving that our pups have engaged in some amorous activity with their wild cousins over the centuries.

This intermingling of dog DNA in wolves is more common in Europe and Asia than in North America.

The researchers who conducted the study note that while wolf-dog interbreeding is a known phenomenon, the extent to which our dogs’ DNA has entered the wolf population is a bit of a surprise.

They say that our idea of what a “pure” wolf is needs to be revised, since so much hybridization has occurred.  A wolf that may look wild may actually be a hybrid with some dog DNA.

What have been the main causes of wolf-dog hybridization over the years?  Free-ranging (and unaltered) dogs, shrinking wolf population sizes, and unregulated hunting, say the experts.

Interested in learning more?  You can read the full article HERE.

 

GOdogs Project Investigates the Genetics of Canine Obesity

The scientists at the University of Cambridge Metabolic Research Laboratories are looking for a few good—and chubby—dogs!  Their GOdogs Project is conducting cutting-edge genetic research on why certain dog breeds tend to become overweight (Labrador Retrievers, we’re talking to you!).  They also hope that this research will shed light on the genetics of human obesity.

If you own a Labrador and live near the Cambridge University Veterinary School in the UK, your dog can become an important part of this ongoing study.  The researchers also welcome input from the owners of other types of dogs.  Owners of all dog breeds can answer a questionnaire about their dog’s eating habits, and if you have a Retriever, Pug, or Bulldog, the Project is looking for DNA samples from your pup.  Click HERE to learn more about participating in the study.

The GOdogs website has lots of great information about obesity in dogs.  Did you know that between 34 and 59% of dogs can be classified as overweight?  Obesity causes significant health problems in our pets, including:

• Joint disease
• Heart and lung problems
• Hormonal disorders
• Incontinence
• Cancer
• Shorter lifespan

Why are so many dogs overweight?  The Project points to the modern lifestyle of pampered pets as a prime cause.  Your dog’s body stores fat as an energy reserve to draw on in times when food is scarce.  Today’s dogs aren’t running around and hunting, so a sedentary lifestyle combined with lots of food that’s high in fat and calories can lead to obesity.

The fact that some dog breeds are prone to obesity suggests that genetics play a role in this, particularly when it comes to appetite and hunger.  Previous studies on obesity in humans and other animals have shown that certain genes affect a part of the brain that controls hunger called the hypothalamus.

What about the link between genetics and obesity in dogs?  The GOdogs Project has been collecting canine eating behavior and genetic data since 2013.  In 2016 they published their first findings about a genetic cause for obesity in Labradors.  One particular gene called POMC has been found to be associated with obesity in Labradors (and flatcoated retrievers).  A quarter of UK Labs have this gene and these dogs were found to be around 4 lbs. heavier than Labs without the gene.  POMC plays a role in regulating feelings of hunger and fullness.

Whether your dog has a genetic predisposition to being overweight or not, there are practical steps you can take to manage your dog’s weight.  Check out these strategies for monitoring your dog’s weight, regulating food intake, minimizing your dog’s feelings of hunger, and making sure your dog gets plenty of exercise, all courtesy of the folks at GOdogs.

 

Scientists Create a Dog Breed “Family Tree”

At first glance, a new visual representation of the canine family tree looks more like a pinwheel than a maple, but the researchers who recently mapped out a genetic history of over 160 dog breeds (published in the journal Cell Reports) have provided us with fascinating new insights into the evolution of dog breeds and how they are related to each other…and human history.

Click image to enlarge.

A study was conducted on the genetic data of 1,346 dogs representing 161 different breeds from all over the world.  The researchers discovered that while many breeds are interconnected, there are also some interesting outliers that have few connections with other breeds.  The connections between breeds can happen by chance, with human migrants who bring their dogs with them to other parts of the world, or through direct human intervention via cross-breeding.

As an example, the researchers highlight genetic variation among three breeds in the study (the Tibetan Mastiff, Saluki, and Cane Corso).  DNA collected from populations of these dogs in the US was quite different than DNA collected from the breeds in their countries of origin.  For example, American Cane Corso dogs show much more evidence of intermixing with other breeds (Mastiffs and Rottweilers) than those in their country of origin, Italy.

What are some other interesting findings of the study?

The researchers were able to confirm historical accounts of our creation of bull terrier breeds (for the purpose of dog fighting) through genetics.  All bull and terrier crosses can be mapped to the terriers of Ireland during the years 1860-1870, according to the study.

Speculation that the domestication of dogs first occurred in Central and East Asia is confirmed by genetic testing that identifies Asian spitz-type dogs as among the very earliest breeds.

Dogs traveled from Asia to the Americas 10,000 years ago with the first human migrants.  But the original New World dogs, like the distinctive Xoloitzcuintle, eventually encountered the dogs brought to the Americas by later European migrants and extensively interbred with them, especially herding breeds.

The authors point to two breed types—sighthounds and livestock guardian dogs—as examples of how breeds can develop in different geographic regions (the UK and the Mediterranean in this case) and share similar characteristics but not the same genetic material.  So a trait like speed or large size can be developed in isolation, but the resulting dog can be similar to unrelated dogs from other areas.

Interested in learning more?  You can read the full text and see more illustrations HERE.