Prevalent obesity is a problem that would surprise our ancestors. In many populations, such as the Inuit of Canada, dramatic changes in lifestyle have inflated waistlines within the span of a few generations. However, the timeworn observation that even similarly behaving individuals vary in body size spurs the search for genetic, as well as environmental, causes of obesity. In the October issue of Genome Research, Robert Hegele (University of Western Ontario), Philip Connelly (University of Toronto) and colleagues have discovered that variations in a gene called GNB3 correlate with obesity in a group of Canadian Inuit.
The gene GNB3 encodes one member of a protein family (called G-proteins) that helps cells translate and respond to chemical signals in their environment. Scientists have shown that individuals who possess a common modification of GNB3 known as GNB3 825T may be susceptible to high blood pressure, a typical complication of obesity. To examine whether the 825T variant in fact associates with obesity, Hegele and colleagues studied 213 Canadian Inuit. For each subject, they measured traits such as weight, weight corrected for height (body mass index or BMI), waist and hip girth and determined the presence of 825T. Individuals possessing only the 825T variant of GNB3 had significantly higher BMI, waist and hip girth, indicating that this variant does associate with greater body fat. This discovery will help scientists understand - and perhaps ultimately treat - the phenomenon of rising obesity in the Canadian Inuit.
Contact information:
Robert Hegele
Robarts Research Institute and Department of Medicine
University of Western Ontario
London, Ontario
Canada
Email: robert.hegele@rri.on.ca
Fax: (519) 663-3789
Genome Research