April 25th is National DNA Day which commemorates the description of the double-helix structure of the DNA on the same day in 1953. The structure explained how the DNA molecule replicates itself, carrying the genetic information of the organism to it’s offspring. The understanding of the DNA structure led to further discoveries like how protein is synthesized using the genetic code stored in the DNA in 1961. The knowledge of the sequences in the DNA led to discovery of the genetic mutation that causes Cystic Fibrosis (Brief History: From Mendel to the Human Genome Project, n.d.). The genetic test for Cystic Fibrosis is now routinely used to screen couples and newborns for the disease. This link, from an online exhibition of the National Museum of Natural History and the National Human Genome Research Institute, contains a brief history that led to the discovery of DNA and beyond.
Tracing the origins of SARS-COV-2
SARS-COV-2 is the coronavirus behind the acute respiratory disease called COVID-19, which is currently affecting the world population. Using modern DNA technology, scientists were able to sequence the virus’s genome quickly from 24 different samples early during the outbreak. By comparing the sequences of the virus among the 24 different samples, it shows limited variation which meant that these samples had a relatively recent common ancestor, one that mutated a month before December 8, 2019 report of the first known case (Begley, 2020). Additonally, by comparing the sequences with other known virus, it was noted that there was 96% similarity with a bat coronavirus, suggesting the bat species as the original source. The advances in DNA technology can help trace the origin and prevent or identify future outbreaks.
Detecting COVID-19 in people
COVID-19, as of 2021, is a worldwide pandemic affecting about 144 million people according to worldmeters.info website. It has forced lockdowns in many countries in order to reduce the spread of the disease which in turn affected the economies of many countries. Detecting people with COVID-19 will help isolate the infected from the rest of the population, thereby reducing the spread of the disease. Currently, one type of diagnostic test for COVID-19 uses the Reverse Transcription Polymerase Chain Reaction (RT-PCR) technique to detect complementary DNAs of SAR-COV-2 virus from the infected patient’s respiratory samples (Udugama et. al, 2020). The technique transcribes the RNA of the virus into complementary DNA and then amplifies it to detect the sequences. This DNA based test is more sensitive than other tests like the antigen tests and the results are known within 24 hours. There is a CRISPR (used in gene editing) based “lab-in-a-chip” diagnostic test which can return accurate results within 30 minutes (Myers, 2020).
Protecting people against COVID-19
To prevent the spread of COVID-19, people need to be vaccinated from the virus that causes it. However, it takes about 10 to 15 years to develop, test for safety and efficacy and approve a vaccine. With advances in DNA research based technology, two COVID-19 vaccines were developed under an year without cutting corners with regards to safety (Solis-Moreira, 2020). The ability of scientists to quickly sequence the genome of the SAR-COV-2 allowed them to analyze the coronavirus much quicker. This allowed them to identify the “spike ” S protein that penetrates the cells and infects the person. Another DNA based technology that helped to quickly create the COVID-19 vaccine is mRNA vaccine technology. Synthetic mRNA is engineered to make cells generate the same S protein but without having a weakened virus to do so ( Pardi et al. , 2018). This “trains” the immune system to recognize and fight off any invading SAR-COV-2 viruses. It is also easier to “tweak” the mRNA strand to target mutant strands of the SAR-COV-2 virus. Nucleic acid therapeutics, be it mRNA, DNA or protein based opens a new way of vaccinating people from diseases.
Combating COVID-19 in infected people
In the United States, 3.9% of the people infected with COVID-19 die from it and 5% have needed intensive care at the hospital (Nebraska Medicine, 2020). During the initial stages of the pandemic, hospitals were overwhelmed with patients as the disease spread quickly and there were no known treatments at that time. Monoclonal antibodies (mAb) treatment is one way to treat COVID-19 patients. An example of this treatment from Renegeron uses a genetically engineered strain of mice that has human immune systems to create antibodies that recognizes the S protein that causes the infection. These antibodies and others from recovering patients have to be identified and synthesized using DNA sequencing and other techniques (Regeneron, n.d.). This treatment was used successfully when President Trump was infected with COVID-19. Monoclonal antibody treatment along with DNA related research holds promise for better treatment approaches for many diseases.
DNA technologies like Next-Generation Sequencing and others holds the promise of providing advanced treaments to many debilitating diseases, current and future. All this can be traced to the discovery of the DNA structure on April 25, 1953.
The Spanish translation of this article is here.
Brief History: From Mendel to the Human Genome Project. (n.d.). Genome: Unlocking Life’s Code. https://unlockinglifescode.org/timeline?tid=4
Begley, S. (2020, January 27). DNA sleuths read the coronavirus genome, tracing its origins. STATNews. https://www.statnews.com/2020/01/24/dna-sleuths-read-coronavirus-genome-tracing-origins-and-mutations/
Udugama, B., Kadhiresan, P., Kozlowski, H. N., Malekjahani, A., Osborne, M., Li, V., Chen, H., Mubareka, S., Gubbay, J. B., & Chan, W. (2020). Diagnosing COVID-19: The Disease and Tools for Detection. ACS nano, 14(4), 3822–3835. https://doi.org/10.1021/acsnano.0c02624
Myers, A. (2020, November 19). A new genetic microlab can detect COVID-19 in minutes. Stanford School of Engineering. https://engineering.stanford.edu/magazine/article/new-genetic-microlab-can-detect-covid-19-minutes
Solis-Moreira, J. (2020, December 15). How did we develop a COVID-19 vaccine so quickly? MedicalNewsToday. https://www.medicalnewstoday.com/articles/how-did-we-develop-a-covid-19-vaccine-so-quickly
Pardi, N., Hogan, M., Porter, F. et al. (2018, January 12). mRNA vaccines: a new era in vaccinology. Nature Reviews Drug Discovery. https://www.nature.com/articles/nrd.2017.243
Nebraska Medicine: COVID-19 can wreck your body, here’s how. (2020, July 17). Nebraska Medicine Omaha, NE. https://www.nebraskamed.com/COVID/what-the-coronavirus-does-to-your-body
Regeneron. (n.d.). PIONEERS IN ANTIBODY RESEARCH. Regeneron.Com. https://www.regeneron.com/science/antibodies