This news release is available in Japanese.
An analysis of the genetic makeup of the Inuit people - who live in an extreme climate, and thus have a diet much higher in energy-rich protein and fat - reveals how this population has adapted to its environment. Assisting their adaptation appear to be a number of genes associated with controlling fat metabolism, height and weight, and cholesterol, among other physiological traits. To gain more insights into the genetic makeup of the Inuit population, Matteo Fumagalli et al. analyzed DNA from 191 Greenlandic Inuit who had less than 5% estimated European ancestry, and compared the results to individuals of European and Han Chinese descent. The team identified a number of genes of interest, including those that are known to control the conversion of omega-6 and omega-3 fatty acids into longer, more unsaturated fats. Further analysis reveals that selection for these genes began before the Inuit population diverged from Native Americans, when their common ancestors lived in or around Bering Strait (the land "bridge" that Native American ancestors used to cross from Asia to North America). Other genes that stood out in analyses include those that are protective against oxidative stress associated with high fat intake, those associated with cardiomyopathy, those that increase energy expenditure to counter obesity induced by a high-fat diet and related insulin resistance, and genes that regulate the differentiation of fat cells. Collectively, this study suggests that the Inuit exhibit a unique suite of genetic variations that have helped them survive on a highly specialized diet rich in protein and fat. This Report is complemented with a Perspective by Sarah Tishkoff.
Article #17: "Greenlandic Inuit show genetic signatures of diet and climate adaptation," by M. Fumagalli; P. Gerbault at University College London in London, UK; M. Fumagalli; F. Racimo; R. Nielsen at University of California, Berkeley in Berkeley, CA; I. Moltke; N. Grarup; L. Skotte; A. Linneberg; T. Jørgensen; O. Pedersen; T. Hansen; A. Albrechtsen at University of Copenhagen in Copenhagen, Denmark. For a complete list of authors, see the manuscript.