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Researchers examining British Labrador retrievers have identified multiple genes connected to canine obesity. The investigations revealed that these same genes, including one called DENND1B, are associated with obesity in humans as well.
The findings mark a significant advance in understanding how biological mechanisms in dogs can shed light on human weight regulation.
Genes Linked to Obesity
The gene DENND1B emerged as the strongest obesity-linked variant in Labradors. It was found to have a direct impact on a brain pathway responsible for regulating the energy balance in the body, called the leptin melanocortin pathway. Four additional genes showing a weaker association with canine obesity were likewise mapped to human genes.
Study co-first author Alyce McClellan, an expert in the Department of Physiology, Development and Neuroscience at the University of Cambridge, explained the significance of these findings.
“These genes are not immediately obvious targets for weight-loss drugs because they control other key biological processes in the body that should not be interfered with. But the results emphasize the importance of fundamental brain pathways in controlling appetite and body weight,” said McClellan.
The Body’s Energy Regulation System
An essential outcome of the research was confirming that DENND1B is present not only in dogs but also in humans, where it is linked to obesity. By focusing on this gene in Labrador retrievers, scientists could better understand how it impacts the body’s energy regulation system.
Researchers hope the insights gained from working with dogs will help clarify how certain neural pathways affect human eating behaviors and metabolic processes. They stress that while these genes are important for understanding appetite and weight gain, they do not present a straightforward target for obesity treatments. This is because the relevant genes are tied to other crucial functions in the body; tampering with them might create unwanted side effects.
Instead, the study highlights the complexity of regulating appetite and energy balance at a genetic level, reinforcing the importance of the leptin melanocortin pathway – a well-known system controlling satiety and hunger.
Food Motivation and Obesity Risk
Among the most striking findings, the researchers noted behavioral differences in dogs that carry the genes most strongly associated with obesity.
“We found that dogs at high genetic risk of obesity were more interested in food,” said co-first author Natalie Wallis, a researcher in the same department.
“We measured how much dogs pestered their owners for food and whether they were fussy eaters. Dogs at high genetic risk of obesity showed signs of having a higher appetite, as has also been shown for people at high genetic risk of obesity.”
This link between genetic risk and food motivation underscores a significant parallel with human cases: individuals who harbor certain genetic profiles may experience stronger cravings for food and need more discipline to maintain a healthy body weight.
Counteracting Genetic Obesity Risks
Interestingly, the study showed that even Labradors with a high genetic propensity for obesity could stay slim if their owners enforced rigorous diet and exercise routines. This is similar to what happens in humans. People carrying particular genetic variants are more prone to weight gain, yet they can avoid obesity by strictly controlling their caloric intake and staying active.
“Studying the dogs showed us something really powerful: owners of slim dogs are not morally superior. The same is true of slim people. If you have a high genetic risk of obesity, then when there’s lots of food available you’re prone to overeating and gaining weight unless you put a huge effort into not doing so,” said senior author Eleanor Raffan, a scientist at Cambridge.
“By studying dogs, we could measure their desire for food separately from the control owners exerted over their dog’s diet and exercise. In human studies, it’s harder to study how genetically driven appetite requires greater willpower to remain slim, as both are affecting the one person.”
The Broader Issue of Obesity
The current obesity crisis is affecting both people and their pets. Between 40-60% of domestic dogs are believed to be overweight or obese, a situation mirrored in humans. The problems range from heightened risk of chronic illnesses to reduced quality of life.
Because dogs live alongside people and share many of the same dietary and lifestyle influences, they serve as a strong model for studying how genetics interact with the environment to determine body weight.
In this project, researchers gathered data from pet owners, measuring each dog’s body fat and “greediness,” then collecting saliva samples to analyze DNA. Comparing various obesity markers with each dog’s genetic makeup allowed them to pinpoint which genes correlated with weight gain. The most powerful variant, DENND1B, was tied to about 8% more body fat in the dogs carrying it.
Subsequent tests confirmed that the same gene variants also show relevance to weight issues in human populations, particularly in groups where single genetic alterations can cause severe, early-onset obesity.
Practical Steps for Owners
Given that dogs with high-risk genes are especially food-motivated, the researchers advise owners to spread out daily food rations or use puzzle feeders that slow consumption. They also suggest choosing nutrient compositions that help dogs feel full longer.
Parallel recommendations exist for people, highlighting the benefits of portion control, diet quality, and strategies to combat overeating cues.
“This work shows how similar dogs are to humans genetically. Studying the dogs meant we had reason to focus on this particular gene, which has led to a big advance in understanding how our own brain controls our eating behavior and energy use,” Raffan said.
The scientists consider these discoveries a springboard for deeper investigations into how genes shape appetite and metabolism in both animals and people.
While the genes identified here may not be immediate targets for obesity drugs, they provide essential clues about the biochemical pathways that drive weight gain. This, in turn, might eventually guide more refined strategies for managing and preventing obesity.
The study is published in the journal Science.
Disclaimer: This article is for informational purposes only and should not be considered medical advice. If you have concerns about obesity, genetics, or diet, consult a healthcare professional or veterinarian for personalized guidance.
