MINNEAPOLIS, June 11, 2008—A gene common to both mice and humans may be partly responsible for the rising rate of obesity that comes with age, according to researchers at the University of Minnesota.

The research was published today in the Proceedings of the National Academy of Science.

Researchers who had been studying the so-called Girk4 gene in mice for its role in heart defects noticed that removing the gene caused mice to gain weight.

The age-dependence of the obesity seen in this mouse model mimics human obesity patterns, researchers said. Indeed, the likelihood of people developing obesity more than doubles between the ages of 20 and 60.

Drug researchers can use this information to create a treatment to this gene, which appears most active in the human brain. Poor eating and exercise habits largely cause obesity, but genes can influence whether people are more affected by those bad habits, said Catherine Kotz, an adjunct professor with the the department of food science and nutrition.

"Definitely, your environment and how you live influences your level of obesity," Kotz said, "but some people are more susceptible to it than others. Genes usually (determine) that susceptibility."

Kotz said this gene appears to affect the appetite. Mice ate more after the gene was removed and also were less active, according to the study.