What is it?
Genetics is the study of heredity and the variation of inherited characteristics. More simply put, the study of how certain traits are passed from parent to offspring.
Why does it matter for dogs?
Dogs are members of our families! Their health, temperament, behavioral issues, breeding standards, and more can all be explained by their genetics. A lot of diseases in dogs are passed down through their genes. Different breeds are often prone to different genetic diseases, such as labrador retrievers and hip dysplasia or Myxomatous mitral valve disease in Cavalier King Charles Spaniels. And, it has been found that genetics is responsible for 60-70% of traits like prey drive, aggression towards strangers, and trainability across differing dog breeds.
The Nitty Gritty of Genetics in Dogs
Genetics works in dogs extremely similarly to how it works in humans. We’ll touch on a few of the basics. When talking about genetics, it's helpful to break it down into genotype and phenotype. A genotype is the specific DNA breakdown or sequence, while the phenotype is the observable expression of that gene. Genes often have alternative forms called alleles. For example, take a lab’s fur. In this case, let’s say the fur can be black or brown. That’s two alleles (black and brown) for one gene (fur). Typically, alleles are dominant and recessive, meaning one dominates over the other one if it's present. In the fur example, black is dominant over brown. So, if the gene variation for black is present, the dog will be black. We can use a dog’s phenotype, like brown or black fur, to help us figure out The genotype present, and vice versa.
There is also intermediate expression, which means the dog is expressing a mix between the two possible alleles. Goldendoodles, for example, often have a mix somewhere in between a poodle’s tight curly hair and a golden retriever’s long soft fur.
Inherited diseases in dogs are connected to dominant and recessive gene mutations. Dogs get ½ of their DNA from their mom and the other ½ from dad. If a mutation is dominant, it only takes one copy of that gene for the dog to have that disorder. Polycystic kidney disease is a dominant mutation often found in Bull Terriers. If a mutation is recessive, it takes two copies for it to be active, such as Degenerative Myelopathy (DM), which is similar to Lou Gehrig’s disease. Because the offspring’s genetic material is made of a mix between mother and father, a dog can be a carrier for a mutation, but not have the disorder. This most often occurs when a disorder is recessively mutated. You wouldn’t see a breeder breeding two dogs that are carriers for DM, as it would greatly increase the chances of the puppies having DM.
There are also things in genetics that seem unrelated but are known as “linked” traits. For example, the coloration merle in Australian Shepherds is linked with blindness. Most merle Australian Shepherds see just fine. However, merle is a dominant trait, so when two merle dogs mate, there is a 25% chance the resulting puppy is blind. This is why people avoid creating “double” merle dogs.
When looking for a reputable breeder, it’s important to have a good baseline idea of the genetics involved. The breeder should do health testing on all breeding dogs, including genetic testing for markers of common diseases/disorders involved in that breed.
If two dogs are bred, their offspring have a mix of ½ the genetic code from each parent. A breeder will take that into consideration to make sure they aren’t breeding two carriers of the same disease or even just dogs with temperaments that aren’t desirable for the breed. Since well-bred dogs are bred to something called a Breed Standard, you can look into your dog’s breed to find out what to expect in terms of health, body structure, grooming requirements, and more. You can even look into the breed’s behavioral concerns such as dog aggression, herding instinct, and digging.
If your dog is a mixed breed, know that they are going to be a mix of their parents. It is impossible to know which traits a puppy will inherit from their parents until they’re already born. Take this into consideration when looking for a new puppy! For example, if you’re looking for a hypoallergenic dog and one of the dog’s parents is not hypoallergenic, it is highly unlikely that the offspring will be hypoallergenic.
Dogs from rescues and shelters are just as important to understand genetically. Unfortunately, we don’t get to know their pasts or genetics when we adopt them. Oftentimes nothing is known about their parents. This just means we get to try a little harder to understand them to give them the best lives possible! It’s highly recommended to get your dog on a regular vet schedule to make sure no health-related surprises come up.
Now, we are lucky enough to have genetic testing on the market for our pets. Tests like Embark can tell you your dog’s breed makeup and if they are carriers for any known/common genetic diseases. This can be especially helpful for our shelter friends whose health we can’t always be sure of.
Nature and Nurture
So, nature or nurture? Which one is more important? In all actuality, BOTH play a massive role in the behavior and health of your dog. It is necessary to both understand and acknowledge our dogs’ genetics (nature) so we can figure out the best way to keep them happy and healthy (nurture).
A good way to do this is in training, dog sports, and games. For example, a greyhound could love going on morning runs with their owner. Alternatively, a beagle might enjoy a long walk with lots of sniff breaks. Taking a look into your dog’s breed, health, and history will help you better understand their needs and can make your bond with them stronger than ever!
Written By: Jax Jackson