In a recent article for The New Yorker, Siddhartha Mukherjee offered an explication of epigenetics that quickly became controversial, inspiring a wave of complaints and commentary among scientists after it appeared. If nothing else, the article's notoriety shows how epigenetics has become one of the hottest corners of contemporary science. I've long been fascinated by the discipline, which shows how specific genes along an inherited spiral of DNA can be switched off and on by epigenes, which hover around DNA and determine how it is activated. The discovery of epigenes has shown that genetics may be a malleable system that can respond to human behavior by locking down or unlocking potential written into the structure of our DNA.
The controversy over Mukherjee's piece arose from his emphasis on histones--a sort of protein packing around the DNA--to the exclusion of RNA and "transcription factors," which are influential proteins that attach themselves to DNA. In either emphasis, the mechanisms of epigenetics has the same outcome: the structure of DNA isn't altered, yet its influence on a human being can be modified during the course of one individual's life. At the very least, Mukherjee has increased visibility for a field that may eventually become one of the most vital branches of science in the future. The article was an excerpt from a book which was favorably reviewed on the front of The New York Times Book Review. No matter how you explain its inner workings, epigenetics maintains that human nature can improve or degrade itself, at least slightly in incremental ways, in the span of a single life.
The author quotes one scientist in the piece: ""There's an epigenetic code, just as there's a genetic code. There are codes to make parts of the genome more active, and codes to make them inactive."
In The Constant Choice, I speculated that epigenetics may eventually show that the choices we make are imprinted on an epigenetic history of our lives, within our own cells, altering how our own DNA is activated. Eventually this could help personal changes in behavior become second nature to a particular individual. It doesn't appear that science has yet demonstrated this conclusively. Yet Mukherjee cites studies of ants that show the death of a queen in an ant colony triggers a wave of changes: the social cataclysm immediately alters the DNA of some worker ants who physically change to become "pseudo queens." They not only behave differently, but live three times longer than ordinary worker ants--even though the basic structure of their shared DNA is identical. The transformation--from little Clark Kents into one collective Superwoman, essentially--is epigenetic.
It isn't hard to imagine that changes in daily habit, making better choices, hour by hour and day by day, can effect a less dramatic but just as decisive change in the way an individual's DNA operates, unlocking potential for a person to become his or her best or worst self. Good habits breed other good habits, and once a set of good choices becomes engrained it becomes easier to maintain--more of an integral part of your own, individual nature. This is easily observable at the level of psychology, but epigenetics suggests maybe these behavioral changes could be supported physiologically.
Whether or not epigenetic changes can be passed down to progeny remains extremely controversial, and Mukherjee dismisses the idea that epigenetics represents a "wormhole" offering a shortcut around Darwin's long process of mutation and natural selection. Yet he tells a story about health issues among grandchildren of a generation of men and women in The Netherlands who were nearly starved during the German occupation of WW II. The health of both children and grandchildren were impacted by the famine, and scientists observed corresponding changes in the epigenetic makeup of those successive generations. (The author observes that this study has been challenged, and research into this group continues.)
It would seem odd, at least to this layman, that, if DNA can be inherited, the configuration of proteins that activate and suppress certain parts of the DNA couldn't also be inherited. If so, then individual human behavior could actually have an evolutionary impact on the behavior of future generations. That's a huge leap, granted. Yet whether or not individual choice can impact the epigenetic structure of DNA in children and grandchildren, doesn't simply that possibility motivate you to do the right thing?
For me, the simple possibility of impacting humanity through "good behavior" is thrilling. The chance that making the right choices repeatedly might actually leave a genetic record aligns with the notion that we can consciously evolve toward a better world, where our behavior increasingly reflects our most cherished values. To bet on this extraordinary possibility should be motivation enough to start making better choices now. One look around at the state of our world only reinforces that resolve.