How The Environment May Be Damaging Health

What is epigenetics? This question is most likely to return a number of answers that would all be some variation of heredity that is not caused by changes in DNA sequence. In other words, epigenetics is not genetics. The emerging field of epigenetics has started to bridge the gap between nature and nurture. What does this mean? We have been aware for some considerable time that our nature is what we inherit from our parents. However, we have not been so clear about how the environment moulds the expression of that which we inherited.

There have been a few forays into this field by researchers, but this has been few indeed and the returns have not been encouraging enough to entice others into the field. The best example of epigenetic changes in biology is the process of cellular differentiation. During the growth of the embryo after fertilisation, a single set of cells called totipotent stem cells change to become the various pluripotent cell lines which in turn become fully differentiated cells. In other words, a single fertilized egg cell gives rise to the many cell types including epithelium, nerve cells, blood cells and vessels through cell division. How does it happen? It happens because some genes are activated while some genes are inhibited.

But now, epigenetics is starting to uncover more details about how disease is acquired or traits inherited. Some of the more recent published studies provide needed clarity by setting down the fundamental concepts and principles of this emerging science. Now, this fascinating scientific field no longer needs to be defined by what it is not.

The field of epigenetics has gained great momentum in recent years and is now a rapidly advancing field of biological and medical research. In recent times, we have been treated to news in the media of women who are going through prophylactic removal of their breasts, mastectomy, because of fears of breast cancer which was found in the family. It is however more important to these women that they are sure they avoid environmental gene activators in the food they eat or the way they cook than what gene they inherited. This is not saying that genetic inheritance has no bearing on disease but there are more important factors that we are losing sight of. However, epigenetics is starting to show us that the fact that there is a gene in the body which makes one susceptible to a particular disease may not be the cause for alarm that we hold it to be. The gene still needs to be turned on, which is a factor dependent on the environment and lifestyle rather than on the presence of the gene alone. Also we are beginning to notice consequences of epigenetics in attempts to clone animals.

The discovery of epigenetics hidden influences upon the genes could affect every aspect of our lives. For example, over the last half a century we have seen the menarche, the age at which a woman becomes biologically mature slide downwards from a range of 14-17 years to a range of 9-12 years! Why? Current findings tie this partly to the pseudo-oestrogens that we pump into the environment from toxic fumes which come from the industries and from motor vehicles.

To many scientists, epigenetics amounts to a heresy, calling into question the accepted view of the DNA sequence as the cornerstone on which modern biology sits. Epigenetics adds a whole new layer to genes that goes beyond the DNA. We are now being forced to recognize that there will be epigenetic responses to environmental change and that this would ultimately have implications, not only for the way in which man will evolve but also that it certainly will have an impact on the wildlife around us. What effect will there be for longevity for example?  Can we silence genes and reprogramme cells? These are great questions that some find profoundly disturbing.

Emerging evidence suggests that epigenetic changes may have an important role in a variety of diseases. Exposures to the use of illicit drugs or alcohol, HIV infection, stresses of all types or disease states may all be correlated with specific epigenomic changes. Epigenetics may begin to grant us an understanding of the complex cascade of events that give rise to chronic heart, lung, and blood diseases.

Biologists have suspected for years that some kind of epigenetic inheritance occurs at the cellular level. Skin cells and brain cells are different in their structure and functions, but they have exactly the same DNA. There must be mechanisms other than DNA that make sure skin cells stay skin cells when they divide. Only recently, however, have researchers begun to find molecular evidence of non-DNA inheritance between organisms as well as between cells. Could we finally be getting evidence that our destruction of the environment is going to affect us more profoundly than we ever thought?