Kristin is a dog agility instructor and competitor with 20 years in the sport.
Picking a Pup
Anyone who has ever looked for their next performance puppy knows the list of desired traits can be long and daunting. I recently got my latest agility prospect pup, and the search was hard. With such a long list of characteristics I wanted in my new pup (good structure, high drive, excellent health, boldness, male, Sheltie, color, size, etc.), how on earth would I ever find him?
I spent a year researching breeders, getting to know lines and following offspring before choosing which breeder's waiting lists to ask permission to join. It was a hard search.
If I had heard about epigenetics when doing my search for the right breeder and breeding pair a year ago, I would have added a couple more questions about my future pup's parents. I would have looked at any long-term, life-altering events the pup's dam or sire may have suffered in their lives. These potential life-altering events would include any that involved long-term high stress or long-term poor nutrition. It turns out, the stresses and nutrition of our dogs may affect their pups' and grandpups' genetic makeup.
Yes, I actually said that stress and nutrition may affect the genetic makeup of a pup. How is that possible? Isn't inherited DNA set in stone and unchangeable? How could stress change DNA?
Actually, the stress doesn't change the DNA, but it can cause DNA genes to be turned "on" or "off." Because of this possibility, the new science of epigenetics should be studied and considered when you go on the hunt for your next performance prospect.
What is Epigenetics?
The "epi" in epigenetics means "above" the genome. The genome is simply the DNA of an individual. The "epi" part is a methyl group—or a group of molecules—that literally sit above the DNA. This methyl group can turn genes on and off.
Until recently, scientists thought our DNA alone made up what we are and what we are to become, but the emerging science of epigenetics is now proving that this methyl group also has influence over what we are and will become simply because of the possibility for genes to turn on and off. Poor nutrition and extreme stress can cause changes in this methyl group, causing genes to be turned on or off.
This is such a new science that when doing research for this article, I ran across several conflicting opinions—and even definitions—of what epigenetics encompass. Scientists are arguing amongst themselves as to what this new discovery will mean. At first, it was thought the epigenetic material would only affect an individual, and that it would not be passed onto the offspring. That has been proven wrong. It is now known that some epigenetic changes can be passed from parents to children, and perhaps as far down the generations to grandchildren.
Epigenetic changes appear to occur with great stress or nutritional deficiencies. Much of these changes can be reversed with a return to a healthy, low-stress lifestyle. The research being done focuses more on long-term stresses and malnutrition such as a study of Holocaust survivors and epigenetic changes in their offspring.
The upshot of all of this interest in epigenetics is that major stresses have the potential to affect short-term heredity.
Picking Your Performance Puppy
Read the above paragraph again. If the stresses of a parent can potentially affect the epigenome of its offspring, it is apparent that a person looking for their next performance pup has something more to add to their dream puppy "want" list. A new puppy buyer may now need to research the nutritional and stress history of the sire and dam and perhaps even the grandparents looking for major long-term, stressful events. Likewise, breeders will need to pay special attention to a healthy, low-stress lifestyle for their dogs.
For instance, a parent from a puppy mill situation would potentially be a poor breeding prospect from an epigenetic standpoint. Perhaps a dog that came from years of living in an abusive environment would not make good breeding stock either. Even if both dogs were wonderful examples of their breed, the stress of their past could affect their epigenome, and that could be handed down to their offspring.
Research into exactly how the epigenome is inherited and what that means for the children is ongoing, but it is believed this inheritance isn't a permanent change for the ancestors of a dog with epigenetic changes. In other words, a dog that has an epigenetic change due to stress or malnutrition may pass on those changes for one or two generations, but it will not be a permanent change in the inherited epigenome.
As this science continues to develop and emerge, one concern is that rescue dogs and dogs with unknown parentage may be overlooked or viewed as "lesser" because of the potential for their parents to have experienced long-term malnutrition or high stress in their lives. It is hoped the general public, who do not need a "bred for purpose dog," will continue to rescue and save these precious lives. One of the draws for many who rescue is the unknown DNA history of their rescues, and that will not change regardless of what the science of epigenetics uncovers. The undying loyalty of these rescued dogs to their owners will not change either.
For rescue dogs who have already experienced malnutrition or stress, science is showing many epigenetic changes can be reversed with good nutrition and a low-stress lifestyle. This is good news for dogs who have already suffered abuse. While it is always good to spay and neuter pets, those pets with this difficult background may become even stronger candidates for spay and neuter procedures.
For those needing a "bred for purpose" dog and who want as stable genetics as possible for this purpose, researching and understanding epigenetics is just another puzzle piece in the search to find the right performance pup. For those not needing this genetic stability for say, a dog with herding drive or a dog with hunting ability, rescuing is and will remain the preferred high road.
A New Science
It is important to stress that epigenetics is a new science. As such, research continues, new discoveries are made, and empirical evidence is further defining and changing opinions. It will be important for the future puppy buyer to research the most current information from studies, and for buyers not to fall prey to some of the more "theatrical" theories involving epigenetics abounding on the Internet.
Remember, epigenetics is the theory gene expression is inherited, but only for a generation or two. They are not a permanent changes to the genome, and therefore they do not cause "evolutionary" or "mutant" changes.
Although I did not take into account any epigenetic history when looking for Aenon, my new performance pup, it didn't matter. His parents have stable, happy lives with low stress, great nutrition, and lots of love. This knowledge eases my mind as I watch Aenon's DNA at work and he grows into an adult sheltie. As time passes, I will continue to provide love and nutrition for him. If at any point in the future he is viewed as potential breeding stock, the owners of his pups can know his epigenetic makeup is as healthy and normal as possible.
Genetics is a confusing, horribly in-depth science, and adding the methyl layer of the epigenome makes the science even that much more involved. It will take decades and longer for scientists to uncover all the information that epigenetics will reveal.
Until then, not only will potential puppy owners be interested in hip, eye, and other genetic tests, they will be asking breeders about the life history of the parents and grandparents, looking for any potential "Holocaust" type stress. Reputable breeders already have well-fed, well-loved breeding dogs, but back yard breeders, puppy mills, and other uncreditable breeders will have another question from potential buyers to fear.
Puppy buyers armed with the knowledge of epigenetics may be able to better find that perfect performance pup.
- The Epigenome at a Glance
This link includes a video that does a great job of explaining epigenetics.
This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.