This 2015 Washington review of epigenetic transgenerational inheritance of reproductive disease defined transgenerational effects as follows:
“In considering transgenerational phenomena it is important to distinguish between direct exposure effects versus germline (sperm or egg) mediated transgenerational events.
When a gestating F0 generation female is exposed the F0 generation female, the F1 generation fetus and the germ cell (sperm or egg) that is inside the fetus and that will produce the F2 generation are all directly exposed. Any effects in the F0, F1 and F2 generations may be due to direct exposure toxicity or to environmentally induced epigenetic changes in the directly exposed cells. Examination of the F3 generation (great grand-offspring) is needed to determine if a transgenerational phenomenon has occurred, since the F3 generation has had no direct exposure effects.
In contrast, in the event an adult male or non-pregnant female is exposed, the F0 generation adult and the germ cells that will generate the F1 generation are directly exposed, such that examination of the F2 generation (grand-offspring) is required to demonstrate a transgenerational phenomenon.”
This review was an example of a government agency commissioning science that narrowly supported their view. NIEHS funded this review, and the authors interpreted “environment” in “Environmentally Induced Epigenetic Transgenerational Inheritance of Reproductive Disease” to fit this conduit of public funds.
The problem was that this interpretation of “environment” limited the subject to the categories pictured in this Venn diagram. The authors’ tailoring of “environmentally induced” to the government agency’s interests should have similarly restricted the title.
Other interpretations of “environment” were in studies such as:
- Epigenetic changes in the developing brain change behavior
- Stress-induced epigenetic DNA modifications may be inherited
and their references. Such studies demonstrated both that:
- Environmental factors like stress and nutrition – especially in early life – cause diseases in later life; and
- These diseases may be inherited by the subjects’ descendants.
Have you ever heard that our children and then their children could possibly inherit our diseases caused by stressful environments? Wouldn’t that research be of equal to or greater importance in our lives than pesticides’ harmful effects?
http://www.bioone.org/doi/10.1095/biolreprod.115.134817 “Environmentally Induced Epigenetic Transgenerational Inheritance of Reproductive Disease”