I love CBC radio. On the weekend I was listening to “Quirks and Quarks” and a discussion of epigenetics caught my ear. Naturally, I had to find out what this things was and how it works.
For many years the research into autoimmune diseases and chronic conditions like cancer has focused on lifestyle and environmental impacts. These diseases have a heritable component but they are not absolutely genetic, leading researchers to try to identify why and this has led into the field of epigenetics. Epigenetics looks at the small markers that attach themselves to our DNA, especially in utero and in early life. These markers do nothing to change the DNA you are going to pass on to your child, they simple alter how that DNA expresses itself. Think of them as the controllers – they can turn things on and off or make things louder or quieter.
In this new field evidence is beginning to show how things like childhood poverty, child abuse and mental illness may have physiologically identifiable marks without changing the DNA. Further, exposure to certain substances can also create epigenetic changes even late in life. Many of the substances considered carcinogenic act this way. They do not alter your genes, they turn on, or turn up, genes you already have (‘genetic predisposition) increasing the growth and success of cancer cells. This brings in the fact that they can not affect genes you do not have and if you have the gene and nothing turns it on, you won’t experience the effects.
I believe that I have seen this in action in my family. My maternal grandfather and both of his daughters (my Mom and my aunt) have died of very similar, very aggressive lung cancers – but not my uncle. In the cases of my grandfather and my mother they also died at about the same age (51 and 52), but my aunt survived until she was in her middle 60’s. Strong genetic evidence – early onset, aggressive, similar patterns of meta – why did my aunt live the extra decade? I believe the simple answer is – she didn’t smoke. My grandparents and parent were smokers meaning life long exposure to the carcinogens in cigarettes. My aunt, though she grew up in a smoking household didn’t smoke herself. Epigenetically speaking, she didn’t turn up the gene. With my uncle, he has passed his early fifties, and is a non-smoker, so the question is, did he get the gene at all? Time shall tell. To contrast this heritage, my maternal grandmother smoked her entire life, and lived until 80, never getting lung cancer. No gene? Seem so.
This is excellent reason for me and my sister – we can’t change our genetic inheritance (and there is not current test for a lung cancer gene, though they do know there is one) but we can choose our lifestyle. Neither of us has ever smoked, neither of us drink as heavily as our parent or grandparent, we eat healthy diets with lots of fruits and veggies, and my sister (not so much me) has kept her weight low. We our doing our part to ensure the volume stays down on our genes, only time will tell if we succeed.
On the human level the field of epigenetics brings weight to our life choices adding to the pressure many feel to “live well”. The weight of a healthy lifestyle becomes a punishing burden as every choice seems to have dire effects not just for themselves but their children. Women especially receive barrages of information and direction on what to eat, drink, and expose themselves to during pregnancy and breastfeeding. I have felt that pressure, but ultimately I try to remind myself that I can only do my best and the stress of trying to manage everything carries as many negatives as a lot of the things we try to manage. I also try to remember that this gives me power, I can impact how my body acts, I am not at the mercy of my genes, how I live, and how I teach my children to live will change what happens to us.
From the perspective of the medical field epigenetics creates a field of unique, crafted interventions that has never existed. We can begin to more clearly understand the most profoundly impacting life events and behaviours to allow both early intervention or to create uniquely personal watch lists given our histories. How intriguing.
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