Genes and Obesity: A Study on Labradors and Humans

Introduction

Pippa, a 12-week-old Labrador retriever, is a perfect example of how genes can influence our behavior and habits. When she hears the word “biscuit”, her entire demeanor changes, and she becomes fixated on getting the treat. This is not just a coincidence, as research suggests that genes play a significant role in determining our weight and appetite.

Genes and Obesity

Our study aimed to investigate the relationship between genes and obesity in humans and dogs. We extracted DNA from saliva samples sent in by pet owners and found that dogs don’t just share a home with their human owners, they also share obesity genes. The top five genes that increased the risk of weight gain in Labradors were also implicated in human obesity.

Why Genes Matter

Both dogs and humans evolved to deal with cycles of food glut and famine. Our brains have mechanisms that drive hunger and satiety to ensure food intake meets our daily energy requirements. Genes influence these mechanisms, but how?

What We Found

The answer lies in the highly selective nature of dog breeding. As a result, it is remarkably straightforward to identify the genes that cause traits, even those like obesity, which come from the net effect of many changes along our DNA. We found that the genes that increased the risk of weight gain in Labradors were not frontrunners in genetic studies of obesity in people. Instead, they were also-rans, with a minor impact on human weight gain.

The Importance of DENND1B

One of the most important genes we found was DENND1B. Dogs who carried the problem version of this gene had around 8% more body fat, but the effect in humans is only subtle. We showed that DENND1B has a previously unrecognised role in the brain’s regulation of body weight, for dogs and humans.

Leptin and Melanocortin Receptors

Leptin is a hormone produced from fat cells in the body. It acts in the brain by activating melanocortin receptors to reduce hunger and increase energy use. The system drives food intake in times of starvation and reduces it when the body has good energy reserves.

Conclusion

Our study highlights the importance of understanding the genetic basis of obesity in both humans and dogs. By identifying the genes that contribute to obesity, we can develop targeted treatments and interventions to help individuals manage their weight. Moreover, our findings suggest that slim people aren’t morally superior, they just don’t need to exert as much willpower to stay at a healthy weight.

FAQs

Q: What was the main finding of your study?
A: We found that dogs don’t just share a home with their human owners, they also share obesity genes. The top five genes that increased the risk of weight gain in Labradors were also implicated in human obesity.

Q: What is the significance of DENND1B?
A: DENND1B has a previously unrecognised role in the brain’s regulation of body weight, for dogs and humans. It is produced alongside melanocortin receptors and alters signaling by them.

Q: What are the implications of this study?
A: Our findings suggest that understanding the genetic basis of obesity can lead to targeted treatments and interventions to help individuals manage their weight. Additionally, it highlights the importance of understanding the nuances of the brain’s regulation of body weight.