The Lab Results Are In: Genes Might Be to Blame for Retrievers’ Obesity

Labrador retriever dogs are one of the most beloved dog breed. Labrador are known for their intelligence, gentleness and intelligence, to be great service dogs. But Labs are known also for their incredible appetite. Labs will literally put in their mouth and eat anything that they can find. It is estimate that nearly 60 % of all labradors are either overweight or obese. 

People think that this trait in Labrador’s breed is just incorrigible gluttons but turns out it’s in their genes.  Scientists at the Cambridge University in fact, have found studying 310 Labrador that many of them either miss the POMC( pro-opiomelanocortin) gene or part of it. Sequencing of the genome of obese Labrador retriever have shown a deletion of 14 bp with an allele frequency of 12%. The deletion of those bases disrupt the production of β-MSH( melanocyte-stimulating hormone) which is associated with increase in body weight, adiposity and food motivation in Labs. Moreover, the deletion was found on both heterozygous and homozygous dogs  showing that this variant in the genome is carried regardless. 

POMC gene regulates the appetite in some species and to sense how much fat the body has stored. If a dog lack this gene it doesn’t know when its full and had enough food so its just keep on eating. This mutation is also more common in Labradors selected to become assistance dogs which is consistent with their training based on food rewards. Labrador in fact for a food reward would work harder hence the higher success on training them for tasks or jobs. The POMC mutation is not a very widespread mutation the only other dog breed that showed it is the flat-coated retrievers which are cousins of the Labradors. Scientists think that the mutation could be associated to St. John’s water dog which the Labrador descend from. The St. John’s water dog was used from fishermen to retrieve nets from the cold water.  

The POMC gene is also present in humans and some rare cases exists of obese people and absence of POMC gene in humans. The gene mutation found in the Labrador could really help understanding more why and how people become obese or are prone to obesity. It is fascinating to me how silly and sweet dogs like labradors are such a genetic mystery not only from POMC gene point of view but also  from an epistatis point of view. So many gene mutations packed in a dog breed is incredible.