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Mouse study
Summary of the mouse study written in language that may be more accessible to those outside the field
Unfortunately, collecting conclusive data about transgenerational epigenetics in human beings is difficult, because there are an almost infinite number of variables to account for.
Still, there is evidence for such changes. Here are a few examples:
Longevity of women correlates to their paternal grandmother’s, but not paternal grandfather’s, access to food during a famine, while men’s survival correlates their paternal grandfather’s, but not their paternal grandmother’s access.* It is important to note that females receive an X chromosome from their mothers and fathers, while males receive an X chromosome from their mothers, but a Y chromosome from their fathers. Women, therefore, are certain to have inherited one of their paternal grandmother’s X chromosomes, while men’s Y chromosome always inherited from their paternal grandfather. The influence of the grandparents’ sexes correlating to the influence on grandchildren indicates an transgenerational epigenetic influence. *This all assumes cisgender typical XX females and XY males. While this is not always the case, the exceptions, for the purposes of this study, are statistically negligent
Babies whose mothers were exposed to cigarette smoke in the womb weighed statistically significantly more than babies whose mothers were not; there is not an equivalent correlation with fathers. Note that all of a females’ eggs develop while they are in the womb, while males’ sperm production does not begin until later in life, and is continually replenished. Therefore, this suggests that the mothers’ eggs experienced epigenetic changes when they were fetuses, which were passed down to offspring, but males’ sperm was not present when they were fetuses, and thus their sperm’s DNA had not been directly exposed to the aforementioned conditions.
If we accept the claim that transgenerational epigenetics play a role in human life, then social factors have even more significance in shaping an individual than we had previously believed.
There are countless numbers of questions which must be asked.
Is it possible that psychological and physical stress placed on Native Americans who were being slaughtered, Black slaves (and Black Americans long after slavery, and continuing to this day), and immigrants during the 19th and 20th centuries, upon whose backs and at whose expense this country built itself, negatively affects their descendants to this day? Would this not morally require that those who reap the rewards of that abuse subsidize the medical bills of descendants, whose DNA carries the genetic “scars” of this abuse?
Should people be allowed to sue those who caused trauma to their ancestors prior to their own birth, if the trauma may have negatively affected their own health?
Is it possible that, for example, steroid abuse, which results in decreased testosterone production, might cause underproduction of testosterone in descendants? What about the effects of countless other prescription medications? If so, is it possible that treating specific medical conditions will make our descendants more likely to suffer from them?
Should egg and sperm donors be questioned about the life experiences of their ancestors?
Could societal trends be results of cumulative biological effects? For example, could low morale during the great depression have resulted in the next generation being more likely to have mental health issues, which caused more stress, which caused the next generation to be more likely to struggle with mental health issues? Even given that this is unlikely, is it possible that such effects exist?
There are countless more questions to be posed and investigated. Perhaps epigenetics can serve to bring together the disciplines of sociology and biology, which have long been considered to be opposites. There is no doubt that it has the potential to revolutionize both fields.
(Images are original assemblies of existing images, used within fair use copyright rules. This post was created as a project for a Sociology course)
