Epigenetics with Dr. Moshe Szyf (Part 1)

Nature or nurture?  For well over a century, the dominant understanding of inheritance was our traits are passed down to us through the DNA code from our parents. But a growing field of study reveals that social factors, environments, and even the experiences your mother faced before you were born all could have profound impacts on your genes. 

Epigenetics is the study of changes to your genes that don't change the underlying DNA. McGill University professor Dr. Moshe Szyf is a pioneering geneticist in this field. His groundbreaking experiments show that social factors, such as maternal care, do change the offspring's ability to adapt to stress and handle anxiety. In other words, these genetic changes happen regardless of who the biological mother is.

Szyf likens DNA and epigenetics to a computer:  Think of DNA as the hardware and epigenetics the apps. Using this analogy, he tells Full Frame, "The mother is actually writing codes in our DNA that tell us what kind of life we’re going to anticipate." 

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[davidjacobson]

This popular story is very misleading. DNA is a static chemical. It is something like a computer memory. The protein and RNA agents that create other protein and RNA molecules based on that memory are something like a complicated computer processor. Across a lifetime, the processing of the trillion or so cells in an human body that are each a complicated chemical machine create continually changing chemical states in every cell. A part of that state is maintained by chemical modifications directly to DNA or to the tails of histone molecules that are associated with specific parts of a DNA structure. The processing that drives this chemistry is partly derived from the original DNA structure and partly derived from the experience of an human being. Nobody really understands that division. But, my evaluation is the growing evidence supports more influence of DNA and less influence of experience than people would like to believe. A smaller part of the picture has to do with transmission of chemical information beyond the basic DNA structure from parents to progeny. There is nothing new in the understanding that a substantial amount of chemical information beyond DNA gets passed from a mother to her child in the egg that is the first cell that starts the formation of the child's body. What is new is the discovery that some amount of information can get passed down through chemical modifications to DNA. This process is highly controlled not some record of random experience. I doubt anyone has any reliable estimate of the information that is getting passed through this kind of method. But, it is very likely to turn out to be a second order effect. Biological science is still a long way from understanding the first order effect that is the extent to which a person's biology is determined by chemical information they receive at birth either from the basic DNA sequence or other parental chemicals compared with the way our chemistry responds to our experiences as we go through our lives. When one of a pair of identical twins develops schizophrenia, the other has a 48% chance of also developing schizophrenia. Some people seem to want to look at that number and proclaim that schizophrenia is not determined by a person's DNA. My reaction is that heredity seems to play a large role.