text: Flipping a Genetic Switch on Obesity? | Bioethics Research Library
  When weight loss is the goal, the equation seems simple enough: consume fewer calories and burn more of them exercising. But for some people, losing and keeping off the weight is much more difficult for reasons that can include a genetic component. While there are rare genetic causes of extreme obesity, the strongest common genetic contributor discovered so far is a variant found in an intron of the FTO gene. Variations in this untranscribed region of the gene have been tied to differences in body mass and a risk of obesity [1]. For the one in six people of European descent born with two copies of the risk variant, the consequence is carrying around an average of an extra 7 pounds [2].
  The team—led by Melina Claussnitzer of Beth Israel Deaconess Medical Center, Boston, and Manolis Kellis of the Massachusetts Institute of Technology (MIT), Cambridge—started with a basic question: where in the body does this variant act to influence weight? For the answer, the team turned to the NIH-funded Roadmap Epigenomics Project.