Researchers at the University of Cambridge have identified a bunch of genes linked to obesity in dogs – and found the very same ones in humans predisposed to putting on weight too.
A group of five genes was found to be the culprit in British Labrador Retrievers, with one called DENND1B having the most profound effect. DENND1B directly affects a brain pathway responsible for regulating the energy balance in the body, called the leptin melanocortin pathway.
The study highlights "the importance of fundamental brain pathways in controlling appetite and body weight,” said Alyce McClellan, one of the authors of a paper published in Science. That means if your Labrador's got a greater-than-usual interest in food, it's down to these five genes in their wiring.
The researchers also noted that there really isn't a wonder drug that might arise from this study. Managing the dogs' exercise and controlling their diet proved to be sufficient to prevent them from becoming obese, even when they possessed the genes that would put them at higher risk of developing the condition.
In fact, it might be best not to consider meddling with DENND1B for the sake of tackling obesity. "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," McClellan explained.
The research team worked with pet owners to measure their dogs' body fat, scored the dogs on a ‘greediness’ scale by measuring how often they asked for food, and collected saliva samples for DNA. They identified the obesity linked genes by comparing the dogs' obesity status with their DNA. The ones with the DENND1B gene had 8% more body fat than those without it.
Next, the researchers examined studies of humans with severe, early onset obesity where single genetic changes were suspected to cause weight gain. That's when they spotted the same five genes first observed in Labradors.
Dr. Eleanor Raffan, who led the study, noted that this research provided a unique insight into how weight gain happens in human physiology. "By studying dogs we could measure their desire for food separately to the control owners exerted over their dog’s diet and exercise," she said. "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."
While it's difficult for us humans to lose weight, we're fortunate to at least have multiple avenues for tackling obesity. If your pooch is in the unlucky DENND1B camp, they'll need your help.
You'll want to manage their food intake and get them to exercise regularly. The researchers also recommend distracting them from constant hunger by spreading out each meal by using puzzle feeders or scattering the food around your backyard so it takes longer to eat.
Source: University of Cambridge
