Imagine a twin - Rahim and Karim. One day they visited a festival where Karim got lost and had ever since lived on the roadside. Rahim grew up in a stable normal family household while Karim grew up with less stability, less access to nutritious food and education but more laborious activity.
Forty years later, Rahim unexpectedly found his long lost sibling. More than the reunion with his brother, what shocked Rahim was the fact that his twin brother was not like him. Karim was shorter than him, had a deeper voice and no longer suffered from any genetically inherited disease that they both had in childhood.
As the traits are genetically inherited, Rahim decided to consult a genetic scientist. The scientist studied their genetic code and found that their DNA is exactly the same as it used to be when they were born. However, it turns out that they don’t just look different but they actually have become genetically different just by living in different conditions despite having the same genetic codes. This is where epigenetics comes in the picture.
Epigenetics is the study of how the environment influences our genetic makeup. According to the national public health agency of the United States, The United States Centers for Disease Control and Prevention (CDC,) it is the study of how your behaviours and environment can cause changes that affect the way your genes work. Unlike genetic changes, epigenetic changes are reversible and do not change your DNA sequence, but they can change how your body reads a DNA sequence.
An example can help to understand it better. Say, our genome is a paragraph and all of the letters and punctuations would be in the exact same order and give the paragraph a meaning. Now keeping the letters in the same order while shuffling the punctuations would potentially change the message of the paragraph for a reader. Similarly, no cell of the body will be able to read and follow the instructions in the DNA sequence as it results in epigenetic changes. Epigenetics literally means ‘above genetics’ where a change is evident without a physical change in the DNA sequence.
What causes epigenetic changes?
Diet, physical activity, smoking, environmental pollutants, family relationships, psychological stress, working on night shifts, financial status and many more are the core causes of epigenetic changes.
How epigenetics works
The genetic mechanism of epigenetics is quite complex following a cascade of biological reactions. Nonetheless, a simplified explanation for the curious minds has been presented.
Genes act as the switch that controls everything our body does. Specific genes are there to do specific functions and show specific traits. This genetic switch needs to be turned ‘on’ or ‘off’ in order for a gene to work. This turning on/off phenomenon is controlled by a chemical (a methyl group) being added or removed from that gene. This phenomenon is called DNA methylation. For example, a gene that is normally supposed to remain off and if a methyl group is added to turn the gene on, then that could result in epigenetic changes.
The placebo effects
Placebo is a substance or treatment, based on the idea that our brain can convince our body into accepting a fake treatment and thus having a cure somewhat. But have you ever pondered about the mechanism behind it? How does a supposedly ‘fake treatment’ magically improve health like real ones? Many would answer it happens because we are conditioned to think that we are getting treated which is partially correct.
Our thoughts influence the level of our hormones which run some of the brain functions. The brain sends signals to the cell to function in a certain way. The cell signals to switch a gene on or off to carry the cellular function. As a result, it all comes down to the regulation of the genetic switch. The bottom line is that our mind-body connection is reinforced by epigenetics.
For instance, the genome is the actual hardware of the computer (your body), then epigenome is more like the software which tells the hardware what to do even though the genome is going to do all the work. The fact is that you can influence your genetic expression.
Interestingly, epigenetic characteristics are passed on to children from parents as well. If somebody is a chain smoker, that’s bad for the individual but it is thought that he wouldn’t necessarily be harming his unborn child in any measurable way. However, this idea is changing pretty rapidly because some of the epigenetic information get stuck on the genomes and are passed from generation to generation. So, if you are a chain smoker, chances are your kids would have more affinity towards smoking than a non-smoker’s kid.
Over the last few decades, numerous scientific studies have been conducted to decode the science behind male infertility. As a matter of fact, the valid cause behind the mechanism of more than 50 per cent of male infertility cases is unknown. Owing to this concern, a number of studies have been conducted, which have inferred that the abnormal methylation of the sperm is highly correlated with male infertility.
Also, epigenetic changes are now considered as one of the hallmarks of many cancers. Disruption of epigenetic processes can lead to altered gene function and transform cells causing malignancies and cancer.
However, as the old saying goes, the cure lies in the problem. Epigenetics both causes and cures cancer. In a study published in the Japanese Journal of Clinical Oncology, it has been found that methylation that takes place in tissues and that is non-cancerous acts as a signal to identify the risk of tumour formation. So, this is emerging as a target for cancer prevention.
The U.S. Food and Drug Administration has approved seven epigenetic drugs for the treatment of haematological malignancies or cancer. Some of these drugs have been acquired from the enzymes that function during epigenetic occurrences.
All in all, from being the cause of some potential diseases and cure of some, epigenetics has enormous advantages. It gives one the power to shape oneself and as a matter of fact, soon epigenetics would be the personalised healthcare tool for individuals.
Shaeri Nawar is a life science researcher. He is currently a research fellow at Asian Network for Research on Antidiabetic Plants (ANRAP). E-mail: [email protected]