Studies have shown that early-life exposure to environmental chemicals can lead to disease much later in life. While scientists have traditionally thought that the negative effects of these exposures are reset in each generation, there are some examples that challenge this notion and indicate exposures can sometimes affect multiple generations. This phenomenon is known as transgenerational inheritance.
Exposure to specific diets or nutritional factors, maternal stress, and certain environmental chemicals have all been reported to induce changes observed at least two generations after exposure, but it is still not clear whether, and how often, transgenerational inheritance occurs in mammals. If the effects of exposure can indeed be transmitted to subsequent generations, this would have major public health implications.
The NIEHS Transgenerational Inheritance in Mammals After Environmental Exposure (TIME) Program funds both exploratory studies that identify and characterize transgenerational inheritance after exposure to environmental toxicants, as well as mechanistic research into known examples of transgenerational inheritance.
Researchers funded by TIME are using mouse or rat models to show that transgenerational inheritance occurs in these animals after exposure to environmental chemicals that are significant to human health and at environmentally relevant doses. Their work will help reveal the genetics and biological mechanisms involved in transgenerational inheritance. Investigators are also examining whether transgenerational inheritance differs between males and females, defining developmental windows of susceptibility, and looking at possible interactions between an environmental exposure and other stressors, such as stress or nutrition, in stimulating transgenerational responses.