Markers on DNA Linked to Obesity: Epigenetic Tags May Influence Disease Risk, Study Suggests
Saey, Tina Hesman, Science News
Chemical modifications to DNA may affect the activity of key genes involved in regulating body weight, a new study finds, raising the possibility that scientists could discover environmental factors beyond calorie intake and exercise that influence a person's size.
The study, published in the Sept. 15 Science Translational Medicine, is also the first to demonstrate that these chemical modifications to DNA are specific to an individual and may affect a person's risk of developing common diseases. Referred to as epigenetic, these changes don't alter the genetic information itself but the way genes are turned on and off.
Studying epigenetics may help scientists learn more about the causes of disease, says Michael Skinner of Washington State University in Pullman, who was not part of the new study. "There's a great deal of disease that is directly influenced by the environment that today we can't explain just using genetics," he says.
In the study, researchers from Johns Hopkins University in Baltimore worked with colleagues in Iceland to map a type of epigenetic change known as methylation in DNA samples taken 11 years apart from 74 Icelandic people. Methylation generally turns off nearby genes.
The team surveyed about 4.5 million spots on the genome of each person and determined how much DNA at each location carried methylation marks. The amount of methylation varied among people at 227 spots, dubbed variably methylated regions.
Of the 227 locations, 119 had the same amount of methylated DNA both times they were measured in all 74 people. …