In developed countries, almost 60% of dogs are overweight. The increased level of obesity mirrors that in humans, implicating factors such as reduced exercise and ready access to high calorie food. However, some dog breeds are particularly obesity-prone, suggesting the influence of genetic factors.

In a study of 310 pet and assistance dog Labradors, Raffan et al. found that a 14bp deletion in the pro-opiomelanocortin (POMC) gene, which results in the disruption of β-melanocytestimulating hormone and β-endorphin, was associated with increased body weight, adiposity and food motivation in both Labrador Retrievers and closely related Flat-Coated Retrievers. In both breeds, for each copy of the deletion carried, the dog was on average 1.9kg heavier.

The mutation was significantly more common in Labrador Retrievers selected to become assistance dogs than was the case in pets. As ‘trainability’ is important in the selection of assistance dogs, and ‘positive reinforcement’ with a food reward is a mainstay of puppy training, it may be that dogs carrying the POMC deletion are more likely to be selected as assistance dogs.

Read the full article in Cell Metabolism doi:10.1016/ j.cmet.2016.04.012