Epigenetics

By Saumya Sharma




DNA diagram depicting the presence of 3 codons and a Methyl Group to display an Epigenetic alteration.


Genetics has focused on the genetic makeup of humans and all living things, but what if there was another, more hidden, force at play? A force that can change our traits and functions without changing our DNA..


Genetics has been hailed as one of the newest scientific fields and is based on the fact that DNA is the code for life. Similar to binary code (which uses only 1’s and 0’s to store and manage data), DNA uses four nitrogenous bases - adenine (A), guanine (G), cytosine (C), and thymine (T) - to write code. A set of 3 of these bases in a row create codons which express traits and create proteins within each person. By this logic, our DNA can tell us exactly how we look, function, and act throughout our life, right? Wrong.


Let's take the case of a set of perfectly identical twins - Jill and Jane. Jill and Jane are the closest we can get to pure copies or clones of a set of 23 chromosomes. Throughout the years, Jill was more athletic than Jane. Jill ran a mile before work every day and ate healthy. Jane, on the other hand, liked to sit down more and enjoyed less “healthy” activities. Logic tells us that Jane is more likely to develop health issues than Jill even though their genetics are practically identical. This is where the mysterious world of Epigenetics lies.


When we look at a double stranded string of DNA we break it into codons. Think of nitrogenous bases as the alphabet and codons as words they create. The series of words - or codons in this case - create a sentence. Now to separate every series of words so that our cells can more accurately synthesise a single protein, we have “stop” and “start” codons. These work like the period and capital letters that start and end sentences. Epigenetics refers to the change in the expressed trait that does not result from a change to the DNA (a change to the DNA would be called a mutation instead). The science behind this uses Methyl groups to hide the “stop” or “start” codon. A methyl group is a molecule that can bind to the outer “vertical rungs'' of the ladder that is our DNA. With the starting of the DNA sentence being blocked, our cell cannot express the given trait or function. Likewise, without the ending of the DNA sentence, our cell cannot stop expressing the given trait or function. Both of these situations can cause changes that vary from minor changes that go unnoticed to major health conditions. The general term for these epigenetic changes is histone modification. This is a fancy way of saying that a “cap” was added to the “stop” or “start” codon and has resulted in a change.


Let's think back to our set of twins again, Jill’s more athletic lifestyle might result in an epigenetic change that causes her metabolism to work faster that what he was born with. So while Genetics focuses on the physical makeup of our DNA, Epigenetics focuses on the actual behavior of it instead.


The potential for Epigenetics is infinite. Epigenetics changes can be addressed faster than DNA mutations since they are small scale and reversible. On top of this, they can result in a new category of medication and treatment for people with various illnesses. With the breakneck speed at which this field is developing, it makes for a fascinating puzzle. There are still mysteries about how to control these Epigenetic changes, as well as if there is a way to reliably control them.