Scientists in China may have discovered how a gene responsible for obesity kicks into action and want to design a molecule to shut it down, according to Reuters. The fat mass and obesity-associated gene (FTO) sits on human chromosome 16, and several studies in the past have shown it is strongly linked to weight gain. But scientists are just beginning to figure out how the gene actually works. "This gene was identified through studies done among different ethnic groups -- Caucasions, Chinese, Japanese and (South) Koreans. It has been established that FTO is associated with obesity," Jijie Chai at the National Institute of Biological Sciences in Beijing told Reuters by telephone. "We believe that FTO is a good target for treatment of obesity. If we can get an active inhibitor (to shut down the FTO gene), we can work towards some sort of therapy." In a paper published in the latest issue of Nature, lead researcher Chai and his colleagues described how their study found the FTO gene was only activated when it binds to what are known as "single-stranded DNA". "It has only activity towards single-stranded DNA and has no activity towards double-stranded DNA," Chai said. "We want to design a small molecule to block FTO activity, to shut down its function. We can feed this (molecule) to mice and see what happens. If the mice get leaner, that would be very exciting," Chai said, but he added that any therapy for obesity would be years away. "We are still a long way off in the search of a drug to prevent (or treat) obesity," he said. The prevalence of obesity is increasing worldwide at an alarming rate and both developed and developing countries are affected, according to the World Health Organisation. In 2005, some 1.6 billion adults over 15 years old were overweight and at least 400 million adults were obese. WHO projects that by 2015, 2.3 billion adults will be overweight and more than 700 million will be obese. At least 20 million children under the age of 5 were overweight globally in 2005. Obesity increases the risk of premature death, diabetes, heart disease, stroke, hypertension and cancer.