Epigenetics – Intergenerational experiences via the DNA

At uni, we watched a BBC documentary called “The Ghost in your genes” (which you can watch here: http://www.youtube.com/watch?v=Q6cQSR3mPm8) It’s about a relatively new area of science called Epigenetics.

Epigenetics refers to the way in which segments of our otherwise fixed DNA can be switched “on” or “off” by external triggers; which results in the manifestation of different human traits. Epigenetics can be thought of as existing in the intersection of nature and nurture as they refer to modifications of the genome that do not involve altering the actual DNA sequence itself but can have fundamental impacts on the way in which organisms develop.

The ease at which epigenomes are affected by environmental factors poses difficult ethical questions around responsibility, intergenerational equity and the embodiment of trauma in individuals who did not experience the trauma firsthand. Epigenetic changes are so interesting because unlike genetic mutations, epigenetic changes are durable and they tend to have an incredibly high rate of being passed on intergenerationally. “Some epigenetic changes leading to cancers and other disease have been found to be transgenerational with nearly 100% penetrance,  in that the altered epigenetic pattern can be transmitted to subsequent generations effectively without being exposed to the original trigger”.

We live in a world that has historically, and continues to, discriminate against ethnicities, cultures, sexualities, religions etc.  The collectively affluent, Judeo-Christian anglosaxen Australian exports more coal than any other nation in the world. We do this, with the knowledge that it is the Pacific Islanders and the Global South who will suffer the natural disasters, rising sea levels and tropical diseases that will accompany the problem of climate change. What are the epigenetic effects of these environmental triggers that could potentially be passed down generation to generation? We know that environmental toxins are not distributed evenly or even randomly on our planet. They are concentrated in the poorest areas, where rates of chronic illness are already higher and there is little access to healthcare.

Epigenetics and intergenerational equity force the meeting of potentially competing priorities of “now” and “then”. Our Western health system, for instance, is geared around treatment (now) rather than prevention (then). Here, epigenetics becomes the circuit breaker because treatment now may cure the body exposed directly to the environmental hazard; but the “toxic effects from agents acting via an epigenetic mechanism [may not be] manifested until one or more generations into the future”so our model of damage and repair may not be effective. This may result in a shift towards corporate and governmental responsibility. Or, “if the most vulnerable people are considered at greatest risk” as they are currently, perhaps there will be no additional resolve to reduce potential harmful exposures because it is not the offspring of white privileged bodies that are going to be affected the first or the most severely.

The capacity for the trauma and experiences of one generation to pass down to subsequent generations via epigenetics presents more ethical and social questions. The BBC film “The Ghost in your genes” explores two examples. One, is a study on the children of holocaust survivors who had elevated levels of a particular stress hormone. The second looked at babies born from women who were pregnant during the 911 bombing and about half of the babies in that sample presented with abnormal cortisol in their saliva. Whilst more scientific research is necessary to prove that this trend is definitely epigenetic; if it is then this has huge implications for the way we understand groups of people who have collectively suffered harm and not only the way individual identity and traits are formed; but the way collective, cultural identities are formed. Many Indigenous Australians talk of a living trauma, that Stuart Hall explains as a product of “the traumatic nature of the ‘colonial experience’”. If this is due to epigenetics (as distinct from intrafamilial communication, shared and communicated cultural history etc.) then very clear legal issues of compensation of restitution arise as well as a new way of looking at the persistently difficult relationship between Indigenous and non-Indigenous Australians.

A final interesting Brave New World-esque consideration is the capacity of epigenetics to feed into Eugenics. Eugenics came about through the desire to improve humanity by increasing the number of people who were genetically well endowed, so to be speak. In effect, this meant reducing the number of people with “undesirable” genetic traits. The horrifying effects of this were seen during Nazi Germany and in the States during the era of forced sterilization. The reason why epigenetics raises these issues once again is because of the nature of epigenetics (environmental trigger that “activates” a part of the DNA sequence) the science suggests that equally these changes can be reversed. Theoretically, this could mean screening embryos in utero and “switching on” the traits you like, and “switching off” the ones you don’t.

I’m really excited to understand more about epigenetics especially to understand how experiences of trauma can be passed on intergenerationally – and the ramifications of this culturally and socially for different groups of people.

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