About half the risk of obesity is determined by the genes people carry, and half of that risk is determined by eight to 10 genes, Christman said. So, the just identified genetic variant, which sits on chromosome 2, is associated with about 5 percent of obesity, he said.
The variant is present in about 10 percent of people around the world, the researchers reported. It is physically close to a gene designated INSIG2, which is involved in fat metabolism. That location suggests it could influence the functioning of the INSIG2 gene, which produces a protein that inhibits production of fatty acid and cholesterol, the researchers said. But more work is needed to say exactly how the relationship between the genes works.
The discovery was made by applying data from the Human Genome Project to people in the long-running Framingham Heart Study and then verifying the relationship in other groups of people around the world, Christman said.
“We think the other nine or so genes will be found very soon,” Christman said. “Others are doing the same thing. Ours is one of the first, but there will be a flood of these over the next several years.”
Every week it seems there are new papers published on genes that influence behavior, including eating disorders – anorexia, for example. So, there should be no surprise that genes governing molecular pathways can alter the manner in which fat is metabolized and produced, leading some individuals to gain weight more easily than others.
There’s also no question that a key factor in familial obesity can also be linked to the type of food your Momma cooked for you – as any survey of shopping carts at the grocery checkout will attest to.