Scientists identifies genes that make humans, Labradors more likely to become obese

Researchers studying British Labrador retrievers have identified multiple genes associated with canine obesity and shown that these genes are also associated with obesity in humans.

The dog gene found to be most strongly associated with obesity in Labradors is called DENND1B. Humans also carry the DENND1B gene, and the researchers found that this gene is also linked with obesity in people.

DENND1B was found to directly affect a brain pathway responsible for regulating the energy balance in the body, called the leptin melanocortin pathway.

An additional four genes associated with canine obesity, but which exert a smaller effect than DENND1B, were also mapped directly onto human genes.

"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 emphasise the importance of fundamental brain pathways in controlling appetite and body weight," said Alyce McClellan in the University of Cambridge's Department of Physiology, Development and Neuroscience, and joint first author of the report.

"We found that dogs at high genetic risk of obesity were more interested in food," said Natalie Wallis in the University of Cambridge's Department of Physiology, Development and Neuroscience, and joint first author of the report.

She added: "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 higher appetite, as has also been shown for people at high genetic risk of obesity."

The study found that owners who strictly controlled their dogs' diet and exercise managed to prevent even those with high genetic risk from becoming obese -- but much more attention and effort was required.

Similarly, people at high genetic risk of developing obesity will not necessarily become obese, if they follow a strict diet and exercise regime -- but they are more prone to weight gain.