Future of our genes…!
An introduction to the genome and some insights into its editing technique…!
The prestigious Nobel prizes for 2020 were declared in the first week of October. This year’s Nobel Prize in Chemistry was of particular interest to me out of all other prizes. The Prize was awarded to Prof Emmanuelle Charpentier and Prof Jennifer Doudna for “the development of a method for genome editing.” During the press conference, the Royal Swedish Academy’s general secretary specifically mentioned that “this year’s prize in chemistry is about rewriting the code of life.” Now you must be wondering what made this year’s prize so special and what it has to do with our typical day to day lives.
To understand the importance of this, we need to brush up on our fundamentals about genetic science. Do you remember reading and learning about DNA? Chromosomes? RNA? A, G, C, T bases? I am sure you all must have read at least some of these words a couple of times during your high school education. But I am 100% sure that you all must have forgotten what they are by now, unless and until your work is related to biochemistry or medical science. Before diving into the research by our Nobel winning scientists, let us clear our fundamentals.
The term ‘genome’ was first used by a German botanist Hans Winkler in 1920 for a gene and chromosome packet. A gene is made up of a molecule called the DNA (or deoxyribonucleic acid). DNA consists of four different blocks — nucleotides, which we know by the letters A (adenine), G (guanine), C (cytosine) & T (thymine). These letters of molecules are connected in a long single strand, and two of these strands come together to form the famous double helix structure of DNA. This DNA is found in the cells present in our bodies. Our body is made up of millions of these types of cells.
A genome is an organism’s complete sets of genetic code — the summation of an organism’s DNA. Each cell in the body, say eye cells, contain this same set of instructions. The genome tells us everything about living things — how they grow, how they live, and how they transfer genes to their offspring (children). Our innate physical similarities to other living organisms — eye color, hair color, skin color, transfer of some types of diseases, etc. result from the information encoded in our genomes.
It is difficult for someone with a non-scientific background (or even for someone with scientific knowledge) to grasp all these things that I am trying to explain here. So, to ease this process, let us try to understand it more thoroughly.
Suppose I give you a pen drive (or a flash drive) loaded with different folders. Each folder contains additional files that can be used to control every device connected to your computer (speakers, mobile phone, iPod, etc.). Now assume that your computer will work correctly when you run all those files together. If there is any defect in any of these files, it will cause the device to malfunction.
The analogy I’m trying to draw here is our genome is like this pen drive containing information stored in appropriate folders and files, ensuring the computer’s smooth functioning. Similarly, the genome has folders — chromosomes, nucleosomes, Gene, and DNA, each containing files/code written with the help of four different blocks A, G, C, and T. If any of these files are corrupt (or there is any defect in them) it can lead to malfunctioning of our bodily systems or what we commonly call a genetic disease or a disorder. A simple erroneous substitution or replacement of any of the letters (A, G, C, or T) can disrupt the whole gene sequence (referred to as a genetic mutation), which causes genetic disorders. Mutations may either occur randomly or due to extreme external factors.
After years of research in genomics, researchers concluded that the best way to treat a genetic disorder is to fix the defective gene making way for the discovery of genome editing methods — doing purposely what nature has done accidentally!
Coming to the point, Prof Doudna and Prof Charpentier’s research is about developing one such genome editing tool known as CRISPR.
Till then, happy reading…!