Chemical modifications to DNA may affect the activity of key genes involved in regulating body weight, a 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 September 15 in Science Translational Medicine, is also the first to demonstrate that these chemical modifications to DNA are unique to an individual and may affect a person’s risk of developing common diseases. Referred to as epigenetic, these changes don’t alter the DNA sequence itself but the way genes are turned on and off.
Studying epigenetic marks may help scientists learn more about the causes of disease, says Michael Skinner, an epigenetics researcher at 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 mapped one type of epigenetic change known as methylation in DNA samples taken 11 years apart from 74 Icelandic people. Methylation generally has the effect of turning off nearby genes.