Labrador retrievers have long been one of the most popular breeds of dog, but they also tend to overeat and become fat. Now, new research from Cambridge University has found a genetic link to obesity in these canines – the first ever discovered in this group of mammals.
Writing in Tuesday’s edition of the journal Cell Metabolism, lead author Dr. Eleanor Raffan and her colleagues reported on the discovery of a DNA variation associated with appetite and weight-gain in these notoriously voracious animals that makes them more likely to pack on pounds.
According to BBC News, the gene is believed to play a key role in controlling how the brains of these dogs recognize hunger, as well as the feeling of satiation after they had consumed enough food. More than one-fifth of all Labradors (23 percent) are believed to carry at least one copy of the variant, and for each copy, the dog was an average of 1.9kg (4.2lbs) heavier.
“This is a common genetic variant in Labradors and has a significant effect on those dogs that carry it, so it is likely that this helps explain why Labradors are more prone to being overweight in comparison to other breeds,” Dr. Raffan explained Tuesday said in a statement.
Research could combat the human obesity epidemic
The gene in question is known as pro-opiomelanocortin (POMC), and it has already been linked to regulating how the brain recognizes the feelings of hunger and post-meal fullness, the authors said. Its discover suggests that the brain of Labradors may be hard-wired for obesity, but the link is “not a straightforward picture,” according to Dr. Raffan.
“People who live with Labradors often say they are obsessed by food, and that would fit with what we know about this genetic change,” she noted. However, she added that “the variant is even more common among flat coat retrievers, a breed not previously flagged as being prone to obesity,” suggesting that there is also something else at work causing these dogs to get fat.
The Cambridge researchers studied more than 310 pet Labradors and assistance dogs. They had each animal weighed and their body condition measured by independent veterinary professionals and then searched for variants of three different potential genes linked to obesity. They also had each dog’s owners provide a “food motivation” profile to disclose the canine’s behavior when it comes to eating.
What they discovered was that a 14 bp deletion in the POMC gene that resulted in a disruption of the melanocyte-stimulating hormone β-MSH and β-endorphin which has been linked to adiposity and food motivation, as well as increased body weight. The mutation was found to be much more common in assistance animals, and the researchers believe that learning more about this variation and POMC itself, could also help combat obesity in people, who also possess the gene.
“There are even some rare obese people who lack a very similar part of the POMC gene to that which is missing in the dogs,” senior author Stephen O’Rahilly, the co-director of the Wellcome Trust-Medical Research Council Institute of Metabolic Science, said in a statement. “Further research in these obese Labradors may not only help the well-being of companion animals, but also carry important lessons for human health.”
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