Genomics in History
From appearance, to behaviour, to health and disease; the genome is the biological recipe that determines what your puppies will become.
Farmers, botanists and breeders have used selective breeding to influence the gene profiles of plants and animals for centuries. They’ve enhanced desirable traits and reduced undesirable ones. They’ve revolutionized agriculture and productivity, and driven vast diversity and segmentation in the appearance and function of both plants and animals. In the canine world, selective breeding has forever tied humans and dogs together: in work, sport, and companionship.
Alleles are the variants of genes that determine a particular trait or phenotype. They influence things like coat colour, herding instincts and friendliness. What the farmers, botanists and breeders of previous generations didn’t know was that their selective breeding efforts were influencing allele frequency: bringing consistency to the characteristics of a given breed or plant variety. Unfortunately, when selecting for desirable traits, our forebears also inadvertently concentrated some undesirable traits and diseases.
Our understanding of genomics has rapidly grown since Watson, Crick and Franklin first described the structure of DNA in 1953. Concepts and tools that were once confined to academia are now available to front line practitioners, consumers, and yes, dog breeders, for a wide variety of purposes. So, the question is, what tools are available to you today and how can you use them?
Screening vs. Diagnosing
Genomic tests for dogs fall into two categories: screening tests and diagnostic tests.
Screening tests allow you to identify dogs in your breeding stock that may be carrying genes or alleles for undesirable traits. This can be especially useful to assess the risk for recessive diseases, cancer and traits that don’t reveal themselves until later in life.
For example, depending on your chosen breed, dilute coat colours may be considered desirable or undesirable. Because colour dilution is a recessive trait, carriers of the gene for dilute colours have a normal appearance. This means that choosing sound parents that are likely (or unlikely) to produce dilute offspring can sometimes be a challenge. Indeed, dilute progeny can occasionally come as a surprise. Screening tests can help remove the guesswork.
In another example, dogs with the dominant mutation of the PKD1 gene can show varying degrees of kidney disease. Some dogs don’t display outward signs of illness until later in life – possibly after they’ve already been bred. To avoid illness and reduce the prevalence of this disease in a breed, screening tests may be used to eliminate affected dogs from a breeding program.
Diagnostic tests are used to identify or confirm a diagnosis when it is already known that an animal is abnormal or ill. More excitingly, diagnostic tests in infectious disease, oncology and other disciplines allow veterinarians to choose precision targeted drugs that can treat conditions more effectively and with fewer side effects.
For example, the genomics of a mast cell tumor can be analyzed at specialized labs. The results of this panel of tests can tell veterinarians about the affected pet’s prognosis, the need to perform additional surgery and what drugs are likely to work best to treat any remaining tumor cells.
Both screening and diagnostic genomic tests should be accompanied by comprehensive explanations of the results, as well as expert guidance on how to apply the information to your particular needs.
Choosing Breeding Stock
We all know about notorious (or infamous) skeletons that live in the closets of our favourite breeds of dogs: hip dysplasia in St. Bernard dogs, dilated cardiomyopathy in Dobermans, Collie eye anomaly in herding dogs, and so on. But, there are several inherited illnesses that are hard to foresee based on breed alone and they can pop up in any kennel, leading to heartbreak, expense and even a hit to your professional reputation.
Think about conditions like cryptorchidism, liver shunts or aggression. Genomic screening can help you identify genes that represent common and uncommon risk factors for illness among your breeding stock. They can inform the pairings that you choose for optimal health and representation of the breed.
Nobody is without problems. Many breeders keep a close eye on their dogs’ health throughout their lives, even when they’ve gone to live with another family.
Careful record-keeping means that you know an awful lot about the health and temperament experiences of the dogs you’ve produced. That means you are also aware of the trends and problems that have revealed themselves over time. Perhaps you’ve noticed a development that you don’t like, related to health, conformation or behaviour.
Genomics can help you to identify some of the underlying alleles that may be driving those traits. With comprehensive profiles of your dogs, you can make breeding decisions that sway the allele frequencies, as well as the phenotypic traits, in the direction you want. A process that used to take many generations of trial and error, can now be accelerated in an informed and cost-effective manner.
Unlocking Precision Wellness and Illness Care
Even with the most careful breeding and husbandry, it is inevitable that some dogs will become sick in their lifetimes. Genomic testing early in life can identify some of the illnesses that a particular dog may be predisposed to.
If a dog carries genes that make them more likely to develop pancreatitis, you can choose a food that helps mitigate that risk. If another dog is at risk for blood clotting disorders, you can work with your veterinarian to make safe surgical plans and emergency protocols. If mutations like ABCB-1 (MDR-1) are known about, the right anesthetic and parasite control drugs can be chosen to safely meet the individual’s needs. If cancer is diagnosed, genomic testing can identify mutations that allow precision drugs to target the tumor, while leaving normal cells alone and healthy.
A Tool Within Easy Reach
Genomic testing is becoming more affordable and more powerful each year.
A variety of tests are available either through your veterinarian, or directly to you, the consumer. Sample material can include blood or tissue samples, cheek swabs or fecal samples depending on your needs. Specialized panels can be provided by companies like Dognomics, Neogen, Embark, and others.
How have genomic tests allowed you to set yourself apart from the pack?