How a Powerful Obesity Gene Helped Samoans Conquer the South PacificGeorge Dvorsky7/25/16 3:16pmFiled to: Geneticsobesitysamoanssouth pacific islandershealthsciencebiologyanthropology10211EditPromoteShare to KinjaToggle Conversation toolsGo to permalinkImage: TransPacificProjectBy studying the genomes of more than 5,000 Samoans, researchers have uncovered a single gene that boosts a person’s obesity risk by upwards of 40 percent. Remarkably, this gene—which appears in a quarter of all Samoans—may have arisen in the population as they colonized the South Pacific. AdvertisementAs described in the latest edition of Nature Genetics, this “thrifty” genetic variant, called CREBRF, is associated with a 1.5 percent increase in Body Mass Index (BMI). So, for a person of average height weighing around 180 pounds, this gene corresponds to an extra 10 pounds. As noted by the researchers in their study, CREBRF promotes more efficient storage of fat and features “an effect size much larger than that of any other known common BMI risk variant.”Working with colleagues from several universities, Stephen McGarvey from Brown University made the discovery while scanning the genomes of thousands of Samoans. This populations has some of the highest obesity rates in the world, a fact that prompted the scientists to conduct a genetic investigation. Around a quarter of all Samoans involved in the study had the genetic variant, which was associated with 30 to 40 percent increased odds of being obese compared to those who don’t have the gene. At the same time, this gene is virtually non-existent in European and African populations and occurs at very low frequencies among East Asians.Advertisement“Although we have found a genetic variant with a reasonable biological mechanism, this genetic variant is just one part of the many reasons for the high levels of BMI and obesity among Samoans,” noted McGarvey in a press statement. Other factors include diet and physical activity. Indeed, the globe’s shift to calorie-rich processed foods and more sedentary lifestyles has contributed significantly to the elevated rates of obesity among Samoans. But as this new study points out, their genetics are also working against them. This gene appears to work by causing cells to store more fat and release less energy. As Alice Klein pointed out in New Scientist, it’s as “if [cells] are trying to conserve as much fuel as possible.” And indeed, there may be a very good reason why this gene appears at elevated levels among Samoans. It has to do with their history of colonizing the South Pacific Islands.