In the battle of nature versus nurture, nurture has a new recruit: epigenetics - brought in from molecular biology to give scientific heft to the argument that genes are not destiny. The overwhelming evidence for genetic effects on our psychological traits conjures up a fatalistic vision for many people, one in which we are slaves to our biology, not in control of our own psyche and our own behaviour. Epigenetics, a mechanism for regulating gene expression, seems to offer an escape from genetic determinism, a means to transcend our innate predispositions and change who we are.
This view is well represented by Deepak Chopra MD and Rudolph Tanzi MD, professor of neurology at Harvard Medical School, who write:
Every day brings new evidence that the mind-body connection reaches right down to the activities of our genes. How this activity changes in response to our life experiences is referred to as “epigenetics”. Regardless of the nature of the genes we inherit from our parents, dynamic change at this level allows us almost unlimited influence on our fate
Epigenetics is important for life and so it follows that it is also important for our psychological well-being. The precisw mechanisms for how changes in the epigenenome affect mental health have not yet been established, but are under investigation. This is a very complicated topic due to all of the factors that have to be taken into account; 1) time in development 2) specific epigenetic change 3) cell type affected 4) location of the affected cell type 5) proportion of cells that have epigenetic change, etc…
Rett Syndrome is a good example of how epigenetics and brain development are linked. This neurological developmental disorder is caused by mutations in MECP2 and is one of the most common causes of female mental retardation. MECP2 is important for DNA methylation, chromatin structure, and ultimately transcriptional regulation. How changes in MECP2 activity lead to mental retardation is still an open question.
As another example of epigenetic alterations at work, substance abuse has epigenetic effects also. Some dull the sensitivity to the drug, requiring higher dosages. Others amplify its impact making behaviour spin rapidly out of control. Epigenetics of abuse can also create the physical stress that triggers whatever predispositions for various diseases a person may carry. It’s complex and still poorly understood
Scientists are working on this, because that would let us cure genetic diseases, some of which kill in early childhood, others of which cause lifelong disability or pain. Advances in whole organism genetic modification are coming fast, but research is very slow because people get all frightened when you talk about experimenting on human cells, even extra embryos created at IVF clinic that will literally be thrown in the garbage if not used for science… but I digress. So far, some techniques show promise, but the hard part is ensuring that only the right genes get changed.
Genes and their expression is highly affected by the lifestyle choices like diet, physical activity, smoking, etc. Poor diet, lack of physical activity and smoking etc. can cause expression of negative genes and suppression of protective genes. So my suggestion for your concern is to maintain a healthy lifestyle as pointed above and you can also seek genetic counselling from an expert who can run special tests on your blood to know more about your genetic profile.
Epigenetics, by current definition, is a modification affecting the genetic expression that is inheritable and reversible. Therefore, yes it can change after birth because after birth your organism is still developing. So, if you take as example a newborn child, his structures need to develop in order to give rise to the adult. Along this developing, most genes need to be inactivated and other - previously uncecessary for the child - need to be activated. So, if you consider DNA methylation as the main mark that states “this gene is going to be off, that is going to be on,“ then a change in DNA methylation has to occur, in order to promote gene expression variation.
On the other hand, if by “reverse bad gene expression and promote healthy gene expression,“ you mean artificially then the answer is still yes. Many drugs have been already synthesized and others are currently in clinical trials, since it has been inferred that dramatic epigenetic alterations may be correlated with tumor malignancy. An example is the Trichostatin A. This drug is used to inhibit the function of histone deacetylase. Of course, this do affect the histones rather then DNA, but still it represents an example that there is a way to change DNA methylation (histone deacetylase is needed for the methylation to follow).
basically a fat person whom starts an exercise regime and loses weight, becomes fitter has changed their epigenetics from bad gene expression to better gene expression.