Epigenetics looks at the changes in an organism through the expression of genes rather than the genetic code itself. To try an even simpler take – it explores the intersection between nature and nurture.
While large sections are simply too technical to understand, Carey does make the overview accessible and understandable, which is a real feat. For example, she uses everyday situations to unpack the science – like why those who drink more can tolerate alcohol more while your tolerance goes down when you stop drinking. This is epigenetics at work – reacting to nature, circumstances and information coming from external factors.
Epigenetics also primarily concerns itself with understanding rare diseases and how they came to be, and how they can be treated by changing gene expressions. The simplest examples of this would be types of breast cancer, or when ageing makes us susceptible to more disease.
Both this book and The Mind-Gut Connection refer to studies like the Dutch famine study – where women who were pregnant during the famine were studied to see what effect the famine had on obesity and health in their children and even in their grandchildren. Women who were in their early or late stages of pregnancy when the famine hit saw completely different outcomes in their children after they grew up and these changes. It’s incredible how much we both do and don’t know about how the body works, about how, when and why genes express themselves, and about the impossible list of factors that can influence this.
If anything, it complicates any ideas we’ve latched on to, taken from headlines or a simple article here and there. Since the science is far more complex, we would do well to do the best we can with the information that we have and not stress too much about the hand that genes dealt us.