By Dr. Becker
Not long ago, researchers at Cornell University wrapped up the largest genetic study of dogs ever undertaken by performing genetic mapping of 4,200 dogs, including purebreds, mixed breeds, and village dogs.1
The study examined 180,000 genetic markers that can help link specific inherited diseases with the genes responsible for them.
According to the Cornell Chronicle, the study is “ … [A] big step toward efficiently mapping genes responsible for complex diseases in dogs, most of which are very similar in humans, thereby accelerating our understanding of human genetic diseases.
By identifying important genes and proteins in dogs for diseases and traits, researchers may then test those homologous genes in humans.”2
Interestingly, there are over 350 diseases that affect both dogs and humans, and there are also similarities in the pathways and genes that cause those diseases.
The research team identified areas on the canine genome associated with hip and elbow dysplasia, idiopathic epilepsy (seizures with no known cause), lymphoma, mast cell tumors, and granulomatous colitis (Crohn’s disease).
Adam Boyko, Ph.D. of Cornell University’s College of Veterinary Medicine and lead author of the study believes the more we understand about the genetic basis of canine diseases, the more successful we can be in keeping purebred dog populations genetically healthy.
“Once you have these loci [DNA segments] identified, the future goal is to develop genetic tests so that breeders can test the dogs before they breed them and then make decisions to help create healthier populations,” says Jessica Hayward, Ph.D., a postdoctoral researcher at Cornell and study co-author.3
The good news for those of us with pets prone to genetic “breed flaws” is the emerging field of nutrigenomics that is proving that what we feed our pets has the power to suppress or unlock DNA.
This means even if your dog tests positive for genetic disease markers, it doesn’t mean he’ll automatically express all his negative genetic potential, which is comforting.
As owners, by positively modulating our pet’s environment — through excellent food choices, reducing chemical exposure and stressors, and focusing on physical fitness — we can dramatically reduce negative gene expression.
Are Genetics Also Shaping Your Dog’s Behavior?
According to Elinor K. Karlsson, Ph.D., an assistant professor at the University of Massachusetts Medical School (UMMS), a dog's personality is shaped by both his life experiences, and also thousands of years of evolution.
“Have you ever known a dog who would retrieve the same ball over and over again, for hours on end?” asks Karlsson, writing for the Conversation. “Or just wouldn’t stay out of the water? Or wasn’t interested in balls, or water, or but just wanted to follow her nose?”4
Karlsson believes these canine traits are the result of hundreds of generations of artificial selection by humans:
“By favoring useful behaviors when breeding dogs,” she says, “we made the genetic changes responsible more common in their gene pool.”5
Interested in Getting Involved in Doggy DNA Research?
To understand how specific genes control the behavior and health of dogs, much more information is needed. That’s why Karlsson and her colleagues have launched a citizen science research project called Darwin's Dogs.
For Darwin’s Dogs, Karlsson is asking dog guardians to record their own observations of their pet’s behavior and personality, and collect doggy DNA at home using mouth swabs provided by Darwin’s Dogs.
Karlsson and her team developed several short surveys to gather pet owner information about their dog’s diet, behavior, personality, and more.
The Darwin’s Dogs project is open to all dogs — purebreds and mixed breeds. The research team will use new DNA sequencing technology and analysis tools to collect genetic information from each dog. The goal is to conduct large-scale studies to facilitate rapid identification of important genes and genetic variants.
Karlsson plans to combine the genetic data from many dogs and look for changes in DNA that relate to particular behaviors. “It won’t be easy to match up DNA with an obsession with tennis balls, for instance,” says Karlsson. “Behavior is a complex trait that relies on many genes.”
Complex traits can be the result of tens or even hundreds of different genetic changes, and in addition, a dog’s environment plays a major role and adds to the complexity.
To be successful, Darwin’s Dogs needs lots of canine companions participating in the research project. Karlsson and her team hope to enroll 5,000 dogs initially. The more dogs they can involve, the more complex biological puzzles they can work to solve. According to Karlsson:
“This is a huge effort, but could offer huge rewards. By figuring out how a genetic change leads to a change in behavior, we can decipher neural pathways involved in psychiatric and neurological diseases shared between people and dogs. We already know these include not just anxiety, but also PTSD, OCD, autism spectrum disorders, phobias, narcolepsia, epilepsy, dementia and Alzheimer’s disease.”6
Karlsson and her colleagues are investigating both canine behaviors and diseases. Their theory is that by locating the genetic changes that led to complex behaviors (e.g., retrieving) and perhaps even personality characteristics, such as playfulness, they can learn more about how brains work.
How to Participate in Darwin’s Dogs
The way the process works is that each participating dog guardian fills out a survey. After doing so, he or she will receive an easy-to-use kit to collect a small amount of their dog’s saliva to be used for DNA analysis. There’s no cost to the dog owner, and the researchers share any information they find. If you want to learn more and/or enroll your own dog in the Darwin’s Dogs citizen science research project, you can do so here.