Exposure to the pesticide DDT could be playing a role in high rates of obesity three generations later, a new study says.
Scientists injected pregnant rats with DDT and found no change in their levels of obesity or their offspring. But by the third generation, more than half of the rats (think of them as the great-grandchildren) showed dramatically higher levels of fat and weight gain, even though they were never exposed to the pesticide themselves.
"Here is an ancestral exposure in your great-grandmother, which is passed on to you and you’re going to pass on to your grandchildren," said Michael Skinner, a professor of biological sciences at Washington State University who led the research published in the journal BMC Medicine.
At work is a disease inheritance phenomenon discovered more than 15 years ago, Skinner said.
A series of experiments on lab rats found that chemicals known as endocrine disruptors, including fungicides, dioxin and bisphenol-A, or BPA, can alter the molecular processes around their DNA without changing its sequence, Skinner said.