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Obesity genes identified

By Sharon Gray

A professor of genetics at Memorial University has discovered 45 genes involved in gaining weight.

Dr. Guang Sun’s research was published on Jan. 5 in the electronic version of the American Journal of Clinical Nutrition, in a paper titled Changes in the transcriptome of abdominal subcutaneous adipose tissue in response to short term overfeeding in lean and obese men.

This paper is the first of its kind in the field of obesity study in the world. The findings are from a study in the laboratory of Dr. Sun, funded by the Canadian Institutes of Health Research.

Dr. Sun said that obesity or uncontrolled weight gaining is the result of chronic positive energy balance or overfeeding.

“It is critical to mimic the overfeeding process to be able to find the genes involved,” he explained. “However, so far all studies used the opposite approach: negative energy challenge including diet and exercise. The main reason is the difficulty to persuade volunteers to gain weight instead of losing weight.”

Dr. Sun’s study combined the power of the whole human genome DNA microarrays with seven days of overfeeding.

“We discovered for the first time 45 genes induced by overfeeding, and six genes displayed a significant interaction effect between adiposity status and overfeeding treatment,” he noted. “These genes may represent a protective mechanism at the molecular level in lean subjects in response to an energy surplus, and they represent valuable candidates for downstream studies related to obesity.”

The 45 genes identified in Dr. Sun’s study are involved in a wide variety of biological process known to be implicated in the development of obesity, including the immune response, lipid metabolism and energy production.

Dr. Sun said the information obtained from this study will provide insights into the genetic targets responsible for individual differences in weight gain. The first author is Jennifer Shea, a PhD candidate in Dr. Sun’s laboratory. The other authors are Curtis R French, Jessica Bishop, Glynn Martin, Barbara Roebothan, David Pace, Donald Fitzpatrick, and Guang Sun, the senior author.