Richard G. Petty, MD

The Epigenetic Code

In Healing, Meaning and Purpose I reveal some of the extraordinary changes that are occurring in our understanding of genetics and inheritance. Even if you are currently learning genetics in college, it is quite likely that some of what your professors are teaching may already be out of date. I say that with the greatest possible respect: I find that in some of my fields of expertise, I am often having to update my teaching materials every week.

One of the remarkable discoveries that is generating huge amounts of new information is what we call epigenetics. This is the study of a form of inheritance that can occur without fundamental changes in gene sequences. This has to do with the idea that there is a second layer of programming on top of our DNA. A code that can change over our lifetimes in response to environmental change. Diet, hormones, chemicals in the environment, stress and even thought, emotion and behavior, can all change the ways in which our genes are expressed. Some of these epigenetic changes can be passed on to other generations. In other words, there can be an inheritance of acquired characteristics. Something that has been denied for over a century.

Let me give you a simple example. Studies of a particular species of mouse have shown that maternal diet has an effect on the coat color of the offspring. This was the result of what is known as methylation that altered gene expression. These changes in coat color were carried on to the next generation: the grandchildren of the mouse given the special diet. This created quite a stir, because it had been thought that epigenetic changes in cells are erased each time that a cell divides. Obviously that was not happening. We now have many examples of epigenetic changes being passed on to the next generation and the next. There are literally hundreds of scientific papers on the subject.

As I have written before in my last book and CDs, in articles and in reviews at Amazon and elsewhere, the traditional view of genetics has been one of genetic determinism. That we are all little robots whose entire lives are dedicated to nothing more than passing our DNA from one generation to the next. And the genes even dictated how we did that. I still know many gene jockeys who are convinced that the whole of human behavior will ultimately be explained by our genes, and that free will is therefore a myth.

I’m just as sure that they are wrong.

Let me give you an example. Identical twins have identical DNA, yet we have known for fifty years that one twin may get a genetic illness that the other does not. And the brains of identical twins, though they start out identical, quickly become quite different from each other because of the impact of the environment. Twin studies of mental illness have been going on at the Institute of Psychiatry in London since 1960. Every patient coming to the hospital is asked by the clerical staff if he or she is a twin. And there has been groundbreaking research on mentally ill twins at the National Institute of Mental Health for decades. And what have we learned? Though there may be a genetic component in schizophrenia, when we look at people with schizophrenia who have identical twins, only half of the twins have the illness, despite having the same DNA. The key difference is at the epigenetic level.

Marcus Pembrey from the Clinical and Molecular Genetics Unit at the Institute of Child Health, part of University College, London, has been at the forefront of the work on epigenetics. Marcus has had the opportunity to study the unusually detailed historical medical records of the isolated northern Swedish city of Overkalix. He and his colleagues found something astonishing. The grandsons of men who experienced famine during mid-childhood went through puberty earlier and had longer life spans, while the grandsons of men who were well fed in early childhood had an increased likelihood of diabetes. For females, the effect was similar but it was tied to the grandmother, rather than the grandfather. Presumably these responses are designed to adjust our early growth and reproduction to be ready for unpredictable changes adverse events in the environment. I would call this epigenetic resilience.

In a separate study done in Bristol in England, Marcus studied two generations of families, and found that fathers who had started smoking before age 11 had sons who were significantly heavier than average. There was no similar effect on daughters.

There is already some evidence that epigenetic factors may play a role in the development of bipolar disorder and schizophrenia.  Many of us are becoming excited about the potential benefit that may flow from a better understanding of genetic and epigenetic mechanisms in major psychiatric disorders.

There is a new journal called, appropriately, Epigenetics that contains a treasure trove of important information. The editor is Moshe Szyf, form McGill University in Canada, and he recently pointed out that one single gene could have as many as 700 epigenetic programs associated with it.

His own research has linked epigenetic change to social interactions: the way in which we behave toward one another can lead to a change in how our genes operate.

Rats whose mothers groom and lick them when they are young grow up to be much calmer than rats whose mothers neglected them. There is, of course, nothing surprising about that. We all understand the importance of good child rearing. But what was surprising was the finding that epigenetic changes are the cause. By nurturing their young, the rat mothers activated a gene that suppressed the creation of cortisol, one of the stress hormones.

Pups who were neglected did not have that gene activated, so they produced more cortisol and were therefore more stressed out.

Knowing this, the researchers were able to increase the well-nurtured rats’ stress by injecting them with methionine, an amino acid commonly found in food supplements.

Here we have proof that the link between food and mood is not just due to transient chemical changes in the neurotransmitters of the brain, but that a chemical in our diet could cause fundamental changes in the way in which our genes work. In this case a rat’s emotions and state of mind. The implications for all of us are extraordinary.

Since 2003, a consortium of public and private firms in Europe has been working on the first Human Epigenome Project (HEP), and it hopes to have completed 10% of the map by the end of this year. As you can see, it is a lot more complicated than mapping the human genome, and epigenetic codes are constantly moving targets. The first reports from HEP have indicated that at least 20% of the genes studied so far can have their behavior modified by the environment. The food that we eat, the chemicals that we ingest and the attitude of our parents and peers can all change the way in which our genes function.

As Marcus Pembrey has said, “Child care has a whole new meaning.”

This is all crucially important, because one of our most important discoveries has been that human beings have been undergoing extremely rapid physical as well as psychological and social change, and that is one of the reasons why the Laws of Healing have been changing over the last century.

About Richard G. Petty, MD
Dr. Richard G. Petty, MD is a world-renowned authority on the brain, and his revolutionary work on human energy systems has been acclaimed around the globe. He is also an accredited specialist in internal and metabolic medicine, endocrinology, psychiatry, acupuncture and homeopathy. He has been an innovator and leader of the human potential movement for over thirty years and is also an active researcher, teacher, writer, professional speaker and broadcaster. He is the author of five books, including the groundbreaking and best selling CD series Healing, Meaning and Purpose. He has taught in over 45 countries and 48 states in the last ten years, but spends as much time as possible on his horse farm in Georgia.


2 Responses to “The Epigenetic Code”
  1. Ananda says:

    Last night on the CBC radio I heard a story about the epigenome that discussed the same studies and principles you bring up in your article. My first reaction was – duhhh yeah, of course that’s how it happens, and then I suddenly got exited, I realized that traditional science was venturing into homeopathic miasmatic theory.

    Miasmatic Theory created By Samuel Hahneman explains that the illnesses, experiences, and states of previous generations affect the health and expression of present generations. That it is from these states that our propensity for chronic disease is established and passed on to future generations. And only by treating a person on the miasmatic level can true permanent health be achieved.

    Diseases such as syphilis, gonorhea, tuberculinum and cancer have all left a genetic and energetic imprint that is passed on. Today we see new diseases changing human expression such as AIDS.

    for more information you can read Chronic Diseases by Hahneman.

  2. Dear Ananda,

    You’ve picked up on what I am trying to emphasize on this blog: that the Laws of Healing have been gradually changing over the last century and that there is ever greater convergence of science and less conventional forms of medicine. Many of which are becoming more effective with the passage of time.

    The point that you raise about miasms is a good one. The original three were all supposed to follow from an infection, but we are now identifying other miasms. Were they always there? Possibly, but probably not: they are emerging as we are changing as a species. And epigenetics do indeed present us with a mechanism for passing on acquired characteristics.

    And another convergence with homeopathy: if you don’t deal with those acquired characteristics, you will be left with a chronic condition that will morph as it becomes more chronic.

    Kind regards,


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