The Genetics of White “Socks” in Our Pets

White paws, often called socks, are an endearing color marking in our pets.  Socks are often seen in cats, but can also be found in dogs and other animals like horses and guinea pigs.

Where do socks come from?  According to a recent article in Popular Science, which outlines some new scientific research on the genetics of coat color, white socks are a form of piebaldism (a genetic mutation that causes white patches of skin and hair).

Before birth, the cells that give color to a kitten’s eyes, skin, and hair (called melanocytes) are concentrated along the back.  During development, these pigment cells move to other areas of the body.

Sometimes the distribution is even, giving the cat a solid color.  But sometimes the color is spread unevenly, leaving white socks on the feet.  Many cats with white feet also have other white areas, such as the chest, belly, and part of the face.  Tuxedo cats are a good example of this.

Interested in learning more about the genetics of coat color in dogs and cats?  Check out this guide to coat colors and patterns in cats…and this one for dogs!

 

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.