Those thousand or more songs in your folder are similar to the DNA sequences or genes and the playlist is similar to epigenetics.
If we had to prepare a blueprint for an architectural design of a building, how would it look like?
How would we start? Every process which goes in to the inception, planning and execution, determines appearance and performance of the final product which we see at the end. Our bodies are quite similar to the complex architectural designs of the buildings. But in our case, where is the blueprint or the information of the design of our body? It is none other than our genes which harbours that information.
Each one of us comprises of millions and millions of cells and every cell contains the blueprints which are our genes. These genes are located in small pocket inside our cells which is called a nucleus. If you were to see the nucleus, you would see some structures like compact bundles of fine threads. These bundles are called chromosomes which comprise of chemical substance called deoxyribonucleic acid (DNA). Genes forms the parts of chromosomes and, therefore are made up of DNA. The structure of DNA is quite unique; it looks like a ladder which is twisted. The ladder contains sequences of information. This information in the DNA would finally determine how we look, function, grow and develop.
Our understanding of genes or genetics describes the way the genes are passed on from one generation to the next which we often call it as ‘inheritance’. However, the information on how should these genes should be used is defined by ‘Epigenetics’. Epigenetics, therefore describes passing on the information about how the genes should be used, from parents to the offsprings. Hence, epigenetic information is heritable but does not depend on the sequence of DNA. ‘Epi’- stands for “on top of” or “in addition to”.
The best way to understand this is the way you organize your music folder in your music player. You may have some thousand or more songs saved in your music folder and you may have some selected songs as a part of your playlists based on the artists, moods, genre or your favourites.
Those thousand or more songs in your folder are similar to the DNA sequences or genes and the playlist is similar to epigenetics. The playlist will have only the
selected songs and will not play the non-selected which will be played, like wise epigenetics will determine which genes should be turned ‘on’ or ‘used’ and
which should be turned ‘off’ or ‘silent’.
How does epigenetics work? Many scientists have been investigating the mechanism of epigenetics and it is currently one of the most interesting research topics. The way epigenetics works is by adding and removing small chemical tags/groups on DNA, which does not change the sequence of DNA, but it changes the ability of the gene to switch ‘on’ or ‘off’ it’s function. There are specific tags which either selects (turn ‘on’) or deselects (turn ‘off’) the gene. One example is DNA methylation, where a ‘methyl’ tag is added to the DNA at specific positions which typically switches ‘off’ the gene. ‘Methyl’ tag is considered as an epigenetic mark, since it does not change the DNA sequence but can turn ‘off’ the function of the gene. Likewise, there are certain epigenetic tags which activate or turn ‘on’ the gene function.
Sometimes the addition or deletion of the epigenetic marks or chemical tags can be unwanted and may lead to diseases. For example: abnormal positioning of methyl tags on DNA is known to contribute to diseases such as obesity, type 2 diabetes, cardiovascular diseases and cancer. It is now known that environmental factors, changing lifestyles, early childhood stress can increase the risk of unwanted epigenetic changes. Therefore, it becomes crucial for us to study these epigenetic changes and its causative factors to gain a better understanding of its impact on human health. The final goal of research on epigenetics would be to eventually help the development of therapeutics and to try to reverse epigenetic changes.
Illustrators: Disha Chauhan and Saurabh Gayali
Edited By: Geeta Goregaonkar
References:
- https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/genes-and-genetics
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3877678/
- https://en.wikipedia.org/wiki/Epigenetics
- https://www.youtube.com/watch?v=kp1bZEUgqVI
Nice graphics!