Gene that may strongly influence obesity found

Scientists have uncovered a "foraging gene" that could play a key role in obesity in humans.
The study examined the gene that the humans share in common with the fruit 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," said Professor Marla Sokolowski from the University of Toronto (U of T) in Canada.
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 the gene called "sitters" are the opposite.

The foraging gene encodes a cell signalling molecule called a cGMP dependent protein kinase. The same could apply to obesity in humans, researchers said.
"When we say the foraging gene is the same, what we are saying is that when you look at the DNA sequences of the human and the fly there is a lot of similarity, enough that you can see it is the fly version of the gene that the human has," said Sokolowski.

"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," said Sokolowski.

Such similarities between species are known as orthologs, meaning they are genes that evolved from a common ancestor years ago, researchers said.
When scientists first started mapping human genomes and comparing them to other organisms, they were shocked to discover humans do not have that many more genes than flies do.
Sokolowski said the research is another part of the puzzle, and the beginning of our understanding of how what was once considered "junk DNA" is actually very important for regulating key characteristics such as behaviour and metabolism.
"No one has analysed it in the way we have in flies, but it is a hint from the fly. The fly has been an excellent model organism to understand mammalian behaviour and metabolism, and so this work can point to places to look further in humans," said Sokolowski.

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 behaviour and metabolism.
Sokolowski said it is particularly interesting that one gene should have multiple roles in feeding and obesity in the body, a characteristic known as pleiotropy.
The research was published in the journal Genetics.