Obesity genes: role of foraging gene in fruit fly

A University of Toronto study on fruit flies has uncovered a gene that could play a key role in obesity in humans. The paper published online this month in Genetics examines a “foraging gene” humans share in common with the flies, which plays multiple roles and is found in similar places, such as the nervous system, in the muscle and in fat.

“What our study does is nails the gene for being very important for the traits of moving, feeding and fat storage,” says University Professor Marla Sokolowski of the Department of Ecology & Evolutionary Biology in U of T’s Faculty of Arts & Science.

In nature, fruit flies called “Rovers” with high amounts of the gene tend to move a lot, eat very little and stay lean, while flies with low amounts of for called “Sitters” are the opposite. The same could apply to obesity in humans.

“So you could imagine if you are a fly, preferences for sugar, the tendency to store a lot of fat and the tendency to move less could all be contributing to the likelihood of being more obese if you have low levels of this gene, or to be leaner if you have higher levels.”

Such similarities between species are known as orthologs, meaning they are genes that evolved from a common ancestor eons ago.

The study involved a technique called recombineering to manipulate DNA at the molecular level, so as to remove and then reinsert the gene in various doses to see the effects on behavior and metabolism.

“To be able to take a gene of this large size and complexity and put it back in the fly so that it works is almost at the edge of what is possible,” Sokolowski says it’s particularly interesting that one gene should have multiple roles in feeding and obesity in the body, a characteristic known as pleiotropy.

The next question would be how exactly it plays multiple roles. “Lots of genes have multiple roles, but the idea here is that this gene may be involved in the coordination of roles in traits important for feeding and obesity.”

 “We don’t know much about pleiotropy, or how it happens, or how it’s regulated at the level of the molecules. So this sets the groundwork to be able to look at that in detail.”

Citation: Allen, Aaron M., Ina Anreiter, Megan C. Neville, and Marla B. Sokolowski. “Feeding-Related Traits Are Affected by Dosage of the foraging Gene in Drosophila melanogaster.” Genetics 205, no. 2 (2016): 761-73.
doi:10.1534/genetics.116.197939.
Research funding: Natural Sciences and Engineering Council of Canada, Canadian Institutes for Health Research.
Adapted from press release by the University of Toronto.