Question

I was once told that if a woman experiences a famine, her grandchildren will show epigenetic changes because the egg that the intervening mother came from also experienced the famine. In other words, the grandchild would be more susceptible to obesity, due to the grandmother's nutritional environment, even though the famine might have been 40-50 years distant. However, I can't remember where I heard this, and could not locate a reference.

Answer 1

Epigenetic inheritance suggests that environmental factors like famine can lead to changes in gene expression that affect future generations, potentially predisposing them to obesity. Studies, including those involving prenatal toxin exposure in rats, demonstrate that these changes can be passed from one generation to the next without the intervening generation being directly exposed to the original environmental insult.

Step-by-step explanation:

The question posed relates to the concept of epigenetic inheritance, which is the idea that environmental factors can cause changes in gene expression that are passed on to subsequent generations. The specific example mentioned involves the impact of a grandmother's exposure to famine on the epigenetic changes in her grandchildren, potentially predisposing them to obesity. This is due to the hypothesis that the environmental signals a fetus receives from the mother can "reprogram" various biological components, including those that control appetite and metabolism. This epigenetic reprogramming may lead to the fetus developing certain phenotypes, such as a predisposition to obesity, which may then be passed down through generations.

Indeed, famines and nutritional deficiencies have been associated with long-term effects on individuals, influencing not only immediate survival rates but also causing long-term impacts on health outcomes such as obesity. The nutritional biology of famines indicates that the timing and severity of malnutrition can have profound and lasting effects on the physiology of affected individuals. Research on famine survivors has shown that those who experienced nutritional deficits in utero may suffer from health consequences in adulthood, and these can potentially be transmitted epigenetically to future generations.

The example provided of pregnant rats exposed to a toxin demonstrates that offspring of the exposed mothers displayed illnesses which persisted even into the subsequent generation, despite the new mothers not being exposed. This suggests that the environmental exposure impacted the epigenetic patterns in the germ line cells of the first-generation offspring, which were then inherited by the second generation.