Researchers studying the British Labrador Retriever have identified several genes related to canine obesity and show that these genes are also associated with obesity in humans.
Dog genes are found to be most closely related to obesity in Labrador Retrievers. Humans also carry
DENND1B gene, researchers found that this gene is also related to people’s obesity.
It was found that DENND1B directly affects the brain pathway responsible for regulating energy balance in the body, called the leptin melanin corticotin pathway.
The other four genes related to canine obesity, but their effects are smaller than DENND1B, and are also directly mapped to human genes.
“These genes are not obvious targets for weight loss drugs, as they control other key biological processes in the human body that should not be disturbed. But the results highlight the importance of basic brain pathways in controlling appetite and weight.
“We found that dogs with high genetic risk of obesity are more interested in food,” said Natalie Wallis, from the Department of Physics, Development and Neuroscience at the University of Cambridge.
She added: “We measured how many dogs make their owners stuff their owners with food and whether they are picky eaters. Dogs with high genetic risk of obesity show signs of higher appetite, which also shows people at genetic risk of obesity.”
The study found that owners who strictly control dog diet and exercise also managed to prevent those with high genetic risk from becoming obese – but require more attention and effort.
Similarly, people with high genetic risk in obesity may not necessarily become obese if a strict diet and exercise regime is followed – but they are more likely to gain weight.
Like human obesity, no gene determines whether dogs are prone to obesity. The net effect of multiple genetic variants determines whether dogs are high or low risk.
The results were published in the journal today science.
“Studying dogs shows us something really powerful: Slim dog owners are not morally superior. So are slim people. If you have a high genetic risk of obesity, you can easily overeat and gain weight when you put in a huge effort without doing it.
She added: “By learning about dogs, we can measure their desire for the dog’s diet and exercise to be controlled by the owners, respectively. In human studies, it is difficult to study how genetically driven appetites require greater will to stay slim because both are affecting a person.”
The current human obesity epidemic is reflected by the obesity epidemic in dogs. About 40-60% of pet dogs are overweight or obese, which can lead to a range of health problems.
Dogs are a good model for studying human obesity: they develop obesity through environmental impacts similar to humans, and because dogs in any given breed have a high genetic similarity, their genes can be more easily associated with the disease.
To get the results, the researchers recruited owners with pet dogs, who measured body fat, scored “greed” and took saliva samples as DNA. They then analyzed the genetics of each dog. By comparing the dog’s obesity status with their DNA, they can identify genes related to dog obesity.
Dogs carrying the genetic variant most associated with obesity had 8% higher body fat than dogs without obesity.
The researchers then examined whether the genes they found were related to human obesity. They looked at these two large population-based studies, as well as similar studies in patients with severe early-stage obesity, suspected that a single genetic change would lead to weight gain.
The researchers say owners can distract dogs from being hungry by spreading daily food rations, such as using puzzle feeders or spreading food around the garden for longer consumption, or by choosing more satisfying nutrients for their pets.
“This work shows genetic similarities in dogs. Studying dogs means we have reason to focus on this particular gene, which has made great progress in understanding how our own brain controls our dietary behavior and energy use,” said Rafen.
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