Hello, and welcome to Research Matters Podcasts. Today, I, Aishwarya Viswamitra, welcome you to part one of our series on the research behind the Nobel prizes of the year 2020! In this episode, we discuss the Nobel Prize in Chemistry. The 2019 winners, Akira Yoshino, M Stanley Whittingham and John B Goodenough, won the Nobel Prize for the development of lithium-ion batteries. This year Emmanuelle Charpentier and Jennifer Doudna won the Nobel Prize for the development of a method of genome editing called CRISPR/cas9.
Our DNA — which makes each of us unique — is made up of subunits called genes. These genes have a variety of functions. It tells us our bodies how to create various proteins. It contains the recipe that tells your body how to develop. In fact, you are able to listen to this podcast because certain genes told your body to make up all the parts of your ears like the eardrum and the auditory nerve leading to the brain.
But, sometimes, because of a mutation or a change in these genes, some people are born deaf. Now imagine a possibility to correct these mutations in the developing foetus and give the person the ability to hear.
Well, this is no longer a far fetched fantasy, thanks to the Nobel Prize-winning technique for genome editing called CRISPR/cas9.
The technique is based on a phenomenon that occurs within many species of bacteria. When a virus infects a bacterium, it injects its DNA into the bacterial cell. If the bacterium survives the infection, it inserts a piece of the viral DNA into its genetic data, carrying it around like a memory! Thus, a part of the bacterial genome is dedicated to viral DNA from all its past encounters, and in between each of these viral DNA segments is a peculiar sequence of DNA. A palindromic sequence of DNA. This entire segment of the DNA, viral DNA plus the palindromic sequences, is called Clustered Regularly Interspaced Short Palindromic Repeats or CRISPR. So why do bacteria create this list of past infections?
The next time a virus infects the bacterium, the bacterium scans it and checks if it matches any part of its CRISPR sequence. If it is, then the bacterium knows that the virus is harmful and has infected it before! It then recruits a protein called Cas9, which cuts the invading viral DNA into pieces and thus prevents it from infecting the bacteria.
This year’s Nobel Laureates in Chemistry asked a simple question. Could this technique be modified to cut any DNA exactly where they wanted it to be cut, remove a particular segment and then join the rest back together? Or, to put in scientific terms, could this method be used to create mutations?
.Emmanuelle Charpentier and Jennifer Doudna figured out precisely that. For every sequence of DNA you want to cut, a matching CRISPR segment can be created in a lab and be used literally as genetic scissors. They were able to replicate this bacterial process in a test tube and simplified it so that it could be used routinely as genetic scissors in any organism’s genome!
They published their paper on this breakthrough in 2012, and a lot has been done in the years since then. Researchers have taken the technique further to not only remove genomic segments but to insert segments as well. The chosen DNA is cut using the CRISPR/cas 9 tool, and a new sequence is inserted in its place. This has revolutionised the field of plant genomics. Scientists have created drought resistance varieties of crops like rice, wheat and maise by inserting a gene that tells them how to survive water shortages.
CRISPR/cas9 has also advanced the field of medicine. Its ability to remove mutated segments of DNA and replace them with the corrected version before the birth of a child is at the forefront of prevailing research. . Researchers are already performing clinical trials to investigate whether they can use CRISPR/Cas9 to treat blood diseases such as sickle cell anaemia as well as inherited eye diseases.
. . However, since this tool can and is altering the future of modern medicine, regulations need to be in place to prevent its misuse. Genetically modified embryos are a major cause of concern — leading to a fear of ‘designer babies’, where parents would be able to create their child to their liking as if in a character creation segment of a video game. But don’t worry! For many years now, there have been laws and regulations that control the application of genetic engineering. Experiments that involve humans and animals must always be reviewed and approved by ethical committees before they are carried out.
But one thing’s for sure — the tool that Emmanuelle Charpentier and Jennifer Doudna created has started a new age in Biotechnology. There’s an entire field of unexplored possibilities ahead, and new and exciting discoveries await us!
Thank you for listening to this episode of Research Matters Nobel Prize series. Stay tuned for the next episode, coming soon! Till then, for more such science news and podcasts, please log on to www.researchmatters.in.