You share 99.5% of your DNA with the person sitting next to you. In fact, you share 97.5% of your DNA with mice. And, believe it or not, 50% of banana DNA is identical to yours! So what makes you so special? Epigenetics.
The New Plastics
Remember the scene in “The Graduate” when the smug, older businessman takes aside the newly minted, baby faced, college grad Benjamin Braddock (Dustin Hoffman) at a party and says: “I just want to say one word to you — just one word — ‘plastics.’” Well, epigenetics is the new plastics. The belief that the genome you inherit from your mother and father is faithfully perpetuated in you is not true anymore. DNA is not your destiny, epigenetics is.
Epigenetics is the non-genetic variation that we see all around us. Even within our own bodies, it explains how different cells, although all having identical DNA, can perform very different tasks, and maintain those tasks for as long as we live. It is why a nose is a nose and why an ear is an ear. Pretty powerful stuff, and stuff that we are just now realizing.
A Genetic Light Switch
Broadly defined, epigenetics includes any process that alters gene activity without changing the DNA sequence. Not only that, epigenetic alterations to DNA are heritable and can be passed to offspring. This little fact makes epigenetics critical to that long, windy road that got us here, also termed evolution.
Several kinds of epigenetic changes to DNA have been described, including methylation, acetylation and other “-ations,” but in general, they serve to “mark” areas of DNA so that affected genes either become active or stay quiet. These marks are both natural and essential to life, but they can also go awry and lead to adverse behavioral and health effects, like cancer, autoimmunity, schizophrenia and autism.
Filling the Gaps of Infertility
Technology can now examine epigenetic marks on DNA on a grand scale, and what’s being learned from such work is fascinating. Take male infertility for example. Most of it is currently unexplained. But epigenomewide studies now suggest that epigenetic patterns in sperm can predict your ability to be a father, both naturally and with the help of assisted reproduction. This has led biotech companies like Episona* to devote their entire existence to figuring out the epigenetic links to fertility. Even more intriguing is the thought that, given the heritability of things, that maybe male infertility is not just about what you’re doing in your life, but also about what your parents’ did in theirs. OK, I’ll stop with the “what’s-beyond-the-universe” thinking, and just leave you with the notion that this epigenetics thing is big in medicine right now, clearly emerging as a ghost-like, parallel universe to the Watson-and-Crick-conceived world of DNA.
*Dr. Turek is an advisor to Episona.