Genetic changes resulting from exposure to certain chemicals in the womb can be passed on through generations, according to new study.
As yet there is no firm evidence of this in humans, but a study conducted by a team at Washington State University showed a clear effect in rats.
According to BBC News, scientists were able to identify specific defects linked to obesity, kidney, and ovary disease.
The study found these defects were caused by a class of chemicals found in certain plastics, environmental pollutants including pesticides, fungicides, dioxins, hydrocarbons, and JP8 — a chemical found in jet fuel.
The field of epigenetics — the study of heritable changes in gene expression or cellular phenotype, caused by mechanisms other than changes in the DNA sequence — has become one of the fastest growing areas of scientific study.
Study leader, Dr Michael Skinner, believes certain chemicals can affect genetic processes if the female is exposed at key points during her pregnancy.
However, scientists stressed the results of their findings are not — as yet — directly transferable to humans, because the levels of chemicals used on the rats were substantially more concentrated than anything a human being would come across, Midwifery Online reports.
In the studies, which were published in the journals PLoS One and Reproductive Toxicology , it was found that rats exposed to chemicals from plastics had offspring with higher rates of kidney and prostate disease, and their great-grandchildren had more disease of the testicles, ovaries and obesity.
In addition, it was found female rats exposed to JP8 (from jet fuel), at the point in their pregnancy when their male fetuses were developing gonads, had babies with more prostate and kidney abnormalities, and their great-grandchildren had reproductive anomalies, polycystic ovary disease and obesity.
“Your great-grandmother’s exposures during pregnancy may cause disease in you, while you had no exposure.”
“This is a non-genetic form of inheritance not involving DNA sequence, but environmental impacts on DNA chemical modifications. This is the first study to show the epigenetic transgenerational inheritance of disease such as obesity.”
Andreas Kortenkamp, professor of human toxicology at Brunel University, told BBC News, the study findings were “potentially very interesting,” but said more analysis was needed before any impact on humans could be determined.
“This is an exploratory study, but the authors themselves are clear that the data do not allow the possible risk to people to be assessed.”
“There is a currently a lack of information about the dose-response relationship, and at this stage we are very unsure about the mechanisms that are involved.”