Transgenerational Inheritance of Environmentally Induced Health Effects
The window of early embryonic development is susceptible to environmental chemical stressors. Exposures during gonadal sex determination may lead to reproductive defects in the exposed individuals. These effects can be transmitted to subsequent generations via germ line (sperm and eggs). Some effects can be transgenerationally transmitted to offspring across several generations. Transgenerational effects are those effects that appear in individuals not because of direct exposure but due to ancestral exposure. Transgenerational phenotypes have been thought to be contributing to declining reproductive fitness and emergence of endangered situation of a species in a natural popuation. In order to provide insights into these critical issues, we are studying molecular alterations occuring during transgenerational inhertitance of phenotypes to identify chemcial and phenotype specific biomarkers associated with adverse reproductive outcomes using medaka fish (d-rR medaka, Oryzias latipes) as a model. We anticipate these biomarkers to be reliably predictive of history of exposure and associated transgenerational phenotypes.
“Nutritional restriction or exposure to hormone mimicking chemicals during early gestation cause alterations in adult and offspring health in humans and model organisms across several generations suggesting that mechanisms associated with transgenerational inheritance of disease states may be conserved”. Picture below shows the toxic effects established by direct exposure may be expressed as adverse health outcome in the exposed individual or may not express at all.
However, such direct effects remain latent for a couple of generations and may emerge as multiple adverse health outcomes in the individuals at later generations. In humans, it is difficult to ascertain such effects but taking a information, that is conserved among comparative models, into consideration effects on future generations of humans can be predicted. We are developing mouse and fish models to identify conserved mechanisms that are specific to environmental stressors and adverse health phenotypes.
Fig. An example of transgenerational phenotype in fish, especially for exposure occurring during early embryonic development.