Example Of Essay On Epigenetics
Epigenetics is a field of biology concerned with the mechanisms that control gene expressions and their accompanying effects. The term literally means “above the genome”, thus this field of study explores how a specific gene is expressed (switched-on) or silenced (switched-off). As cells divide, epigenetic instructions are inherited by daughter cells, but these instructions are not permanent – they, in fact, could be altered. According to the video from NOVA, a science series by PBS, factors such as age, environmental conditions and lifestyle could greatly influence or change the epigenome, which is a set of epigenetic landscapes that regulates phenotypic expressions. Thus, this could explain the fact that in addition to a person’s inherent genetic make-up, several other risk factors could affect the likelihood of developing a disease.
The video further suggests that epigenomes have a larger role in disease development than inborn genomes. An interesting case of identical twins, Clotilde and Ana Mari, showed that even if they have the same genetic make-up, the difference in their epigenomic code was the reason why the latter twin acquired cancer while the former is perfectly healthy. Another concept presented is that like genomes, epigenomes could also be inherited. The harmful effects of food and environmental conditions acquired in the epigenomes of a parent can be passed on to the offspring, thereby progressively increasing the odds of disease development in the succeeding generations. Hence, that brings in responsibility to the present generation, but looking at the other side of the coin, it also brings in hope. The environmental toxins that we acquire may alter epigenomes, and trigger disease development. Alternatively, we can deliberately modify the epigenomes that our children will inherit. Recent studies suggest that it is possible to switch off or switch on epigenomic codes that trigger or prevent the development of diseases such as cancers, systemic lupus erythematosus and myelodysplastic syndrome (MDS).
In a journal article by Bob Weinhold (2006), he discussed that there are ongoing investigations of many drugs that utilize epigenetic mechanisms. They include the following processes – phosphorylation, ubiquitylation, sumolyation, methylation, and acetylation. The last two are the best known processes, primarily because they are the easiest to study with the available technology. In fact, a drug called azacitidine has been approved by FDA for use in the United States to treat myelodysplastic syndrome (MDS), which is a disease in the blood that can eventually progress to leukemia. This particular drug expresses the genes that had been switched off by methylation. However, only 15% of those who take this drug benefit from it. In addition to the low success rate of the drug, it brings about a number of serious side effects as well, such as nausea, fever, vomiting, and anemia. Andrew Feinberg of Johns Hopkins University Center for Epigenetics in Common Human Disease explained the mixed effects of this drug in his study published in the October 2004 issue of the Cancer Cell Journal. Different molecular level effects of this drug include the following – apoptosis and inhibition of DNA replication. He said that aside from switching a number of genes on, it can also switch another number of genes off. His findings suggest one main reason why it is difficult to develop drugs that target specific epigenomes is because of the unintended side effects.
Another interesting epigenetic mechanism discussed in the article is chromatin modification through acetylation, which can ultimately influence gene expression. In general, this process prevents the expression of tightly folded chromatins while more open or functional chromatins are fully expressed. The consequence of such process is called imprinting. In a nutshell, imprinting prevents the expression of damaged alleles that may cause vulnerability to toxins, microbes, and other harmful substances. According to a study by Randy Jirtle of Duke University Medical Center published in the June 2005 issue of Genome Research Journal, approximately 600 genes in mice could be imprinted, and he anticipated that there could be more or less the same number in humans. At present, researchers identified 80 human genes that can be imprinted.
Additionally, the article by Weinhold (2006) discusses compelling evidences that link epigenetic mechanisms, which account for genetic alterations, and cancer development. It was also pointed out that epigenetic modifications can actually last for at least four generations. This is the reason why the family history of an individual is important and has to be present in medical records. This information aids the medical professionals in knowing what particular diseases the individual is at risk of. In my case, common non-communicable diseases such as arthritis, diabetes mellitus type 2, hypertension, and colon cancer are present in our family history. All of the aforementioned conditions are diseases that progress slowly, and their prognosis heavily depends on drug compliance and healthy lifestyle. When I got my results in BlueZones.com, I was not surprised to see that I could actually add almost 18 years in my life span if I optimize my lifestyle.
In the light of the new epigenetic concepts I have learned, ensuring better life expectancy becomes possible through changes or improvement of personal habits. Food intake influences the body’s normal physiology, thus religiously eating vegetables, whole grains, fish meats and fruits as well as avoiding too much intake of salt can definitely prolong life and of course prevent the occurrence of diseases. Regular exercise also helps in optimizing body muscles and preventing disabilities due to old age. Maintaining normal body mass index (BMI) can reduce the risk of developing morbid hypertension and diabetes. Another way of avoiding respiratory diseases and cancers is to stop smoking. In fact, this is one of the few risk factors with established epidemiologic studies that suggest that it is actually a cause of lung cancer. Being protected from the sun can also help in preventing skin cancers. Radiations may trigger epigenome modification, and this may result to genetic alterations. The mental aspect of health is also equally important as the physical aspect because instabilities may cause problems in sleep. This results to stress which may affects one’s daily life. Thus, it is important to keep social circles intact, and maintain healthy relationships with family and friends.
In summary, epigenetics is a very promising field of science. This discipline is extremely important in understanding the mechanisms of diseases, especially the non-communicable ones. The success of vaccine programs eliminated most of the communicable diseases, and I think perhaps the field of epigenetics holds the key in controlling and eventually eliminating non-communicable diseases. Epigenetics also provides proof that personal choices, whether big or small, can ultimately have lasting effects not only for the persons themselves but for their offspring as well.
Holt, S. (Producer & Director). (2007). Epigenetics [Television series episode]. In S. Fine (Executive Producer), NOVA scienceNOW. Arlington, VA: Public Broadcasting Service (PBS).
Weinhold, B. (2006). Epigenetics. Environmental Health Perspectives 114(3): A160-167.