Most of us think of genetics as fate. Tough luck if some of your genes are programmed for trouble. Well, there is ,more to it than that.
It now seems likely that genes can be reprogrammed, through something as simple as a basic shift in attitude or change in life style. It’s the discovery in a field of genetics called epigenetics that has identified a biochemical code carried in our DNA. Epigenome is the name of this code has been given. It acts on genes like a dimmer switch. Epigenomes can turn up the power in genes that make life wonderful and turn down the power in those that make life difficult.
The Unhappy News: Child Abuse and Gene Expression
Researchers recently found evidence of this genetic feature in the brain tissue of people who were abused in childhood and later committed suicide. They found changes in the DNA expression of a gene that regulates the way the brain controls the stress response, intensifying stress reactions and short circuiting the brain’s capacity to calm these reactions. As a result, the history of abuse made these people more vulnerable to anxiety and depression. The environment of abuse had turned the stress gene way up, locking the brain into threat mode and generating a chronic state of stress. It made their lives unbearable. This unfortunate gene expression was not found in postmortem brain samples of people who had no history of childhood abuse.
Twins provide another example of how life experience can affect the manner in which DNA expresses a trait or tendency. At birth, identical twins have identical genes. However, as time goes by, one twin can develop psychiatric problems or cancer while the other does not. Studies show that as twins age, their epigenomes express differently. As a result, their lives turn out differently.
The point is DNA expression can be altered in adulthood. In the case of the stress gene, its expression can be changed to enable the brain to regulate the stress response system more effectively. In one study of men with prostate cancer, researchers found that a three-month program involving a healthy diet, moderate exercise and daily stress management had the effect of turning up 48 genes and turning down 483 genes. 
The Happy News: Love and Gene Expression
It appears that love can also activate epigenomes. Robert Sapolsky of Stanford relates a story about a boy who was severely abused, emotionally and physically. After he became a ward of the court it was discovered that he had zero growth hormone in his bloodstream. Chronic stress had completely shut down his growth system, to the degree of threatening his life. He was hospitalized, and over the next two months developed a close relationship with his ward nurse —undoubtedly the first normal relationship he had ever experienced. To everyone’s amazement, his growth hormone levels zoomed back to normal. When his friend, the nurse, went on vacation the boy’s levels dropped back to zero. Interestingly, it rose again immediately after her return.”
“Think about it,” Sapolsky commented. “The rate at which this child was depositing calcium in his bones could be explained entirely by how safe and loved he was feeling in the world.” The relationship we offer one another may determine the expression of genes involved in securing our well being, emotionally and physically. It appears we are not “victims”of genetics.
“The thing I love about epigenetics,” says Dr. Randy Jirtle, Director of the Epigenetics and Imprinting Laboratory at Duke University, “is that you have the potential to alter your destiny.” 
Forgiveness and Gene Expression
I had an experience in mid life in which an internal change I made altered the way my personality was wired, changing the trajectory of my life. I was abused as a child by my stepfather. At eighteen I left home and for the next twenty years had nothing to do with “that man,” as I called him. As far as I was concerned he was dead and gone. But, epigenetically, he was anything but dead. The years of abuse had chemically encoded my stress response gene for a hair-pin trigger that set off fight or flight reactions, especially the fight version. If someone looked at me crosswise, I became paranoid. If someone got in my face, I blew up. I was not an unlovable and unloving human being. I had a good heart. But under certain conditions, the circuitry operating in me back in my twenties and thirties could turn me into a frightened and frightening person in the blink of an eye. It damaged trust in important relationships and devastated my self-esteem.
Certainly, I was a much better father and husband than my stepfather, but I had to admit to myself there were moments when I couldn’t tell him from me. I knew nothing about epigenetics at that time, but it did seem as if some aspect of his volatility was encoded in my brain, as though inherited. But how could that be, since he was not my biological father?
We now know from epigenetics that it’s probable his abuse coded a gene that set the default in my brain to anger. Someone in his past had done the same to him, and someone before that person, going back generations. I now was part of that epigenetic inheritance and I was passing it on to my children. It was up to me to heal Dr. Jekyll of Mr. Hyde and spare the next generation. To do this, I had to face my past beginning with facing my stepfather.
After years of estrangement, I went to see him. My stepfather had aged and was quite ill, which ironically helped us reconnect. His illness made him humble and vulnerable, which in turn made it easier for us to open our hearts to each other. The result was a process of forgiving that healed my life in ways I could not have imagined. I am convinced that if science had biopsied my brain before and after the journey I made with my stepfather, they would have found that the stress response gene had recoded, quieting neural networks that cause fight-or-flight and amplifying networks that give peace a chance.
Ten years after my stepfather died, I wrote a poem about our journey together. It’s part of a book of poetry I wrote called Fishing for Fallen Light (Wakan Press, 2000). Over the years, I’ve read this poem at workshops and recitals, perhaps a hundred times. I am always humbled by its impact on people who, like me, were subjected to childhood abuse of one kind or another. The poem seems to have a therapeutic effect on people. Perhaps it helps generate an epigenetic change. Who knows? Science is just beginning to understand the way a change in attitude can change our brain to change our life.
I offer this poem to anyone who wants to forgive the past in order to change a gene that can free your future.
 “Epigenetic regulation of the glucocorticoid receptor in human brain associates with childhood abuse.” Patrick O McGowan, Aya Sasaki, Ana C D’Alessio, Sergiy Dymov, Benoit Labonté, Moshe Szyf, Gustavo Turecki & Michael J Meaney. Nature Neuroscience Published online: 22 February 2009. doi:10.1038/nn.2270
 Changes in prostate gene expression in men undergoing an intensive nutrition and lifestyle intervention, Dean Ornish, Mark Jesus M. Magbanua, Gerdi Weidner, Vivian Weinberg, Colleen Kemp, Christopher Green, Michael D. Mattie, Ruth Marlin, Jeff Simko, Katsuto Shinohara, Christopher M. Haqq, and Peter R. Carroll PNAS 2008 105: 8369-8374.
 Robert Sapolsky, “Why Zebras Don’t Get Ulcers: The Devastating Effects of Stress on Children,” Keynote address, Brain Connection to Education Spring Conference, San Francisco (May 11–13, 2000): http://cklrecords.blogspot.com/2006/03/why-zebras-dont-get-ulcers.html.
 Epigenetics: Study of Lifestyle Choices and How They Alter Gene Behavior. Amber Dance, Special to The Los Angeles Times, http://www.latimes.com/news/health/la-he-epigenetics-20100503,0,2006517,print.story, Tuesday, May 4, 2010