The Significance of DNA and Its Importance in Modern Biology

Deoxyribonucleic acid, otherwise referred to as ‘DNA’, is more than just a bunch of nucleotides perfectly organised and orchestrated to form the infamous ‘double helix’. Commonly studied at a molecular level, DNA and its structure have been fundamental in understanding evolution. The importance of DNA cannot be overstated, with it having several applications in many fields. An understanding and appreciation of the structure and function of DNA has opened up many areas of research, such as genetic engineering, which is an area of study of increasing interest. Forensic science and genealogy also rely heavily on DNA fingerprinting and sequencing for information.

DNA is thought of as a blueprint for the body to make proteins. Structurally, a DNA molecule has a sugar-phosphate backbone with base pairs linked by hydrogen bonds, these hydrogen bonds help stabilise DNA’s helical structure. Stability of the DNA structure is achieved through base stacking (hydrophobic interactions). Consider a sentence: the sentence itself is the polymer,  and the letters which compose it, the individual units of the sentence, are its monomers. DNA is composed in a similar way: it is a polymer made up of monomers called nucleotides. There are four different nucleotides: A (adenine), C (cytosine), G (guanine), and T (thymine). Nucleotides are the building blocks of DNA - like the letters of a sentence, they can be arranged in various ways, changing the overall function of the DNA strand [1]. DNA molecules are packaged in chromosomes, storing genetic information; individuals have a different sequence and arrangement of chromosomes, genes and alleles (variants to genes). This unique patterning of genetic material is the basis by which extraction of information about an organism is formed. 

Diseases and medical conditions can be interpreted and understood using DNA: gene mutations that damage DNA have adverse effects on the health and well-being of an individual. A study investigating the significance of DNA concluded that inherited disorders are all passed on through defective DNA, for example, oxidative stress damages DNA to such an extent that germ cells, involved in conception, become damaged. The result, among others, of such damage to DNA is infertility, which is passed down the germ line; childhood cancer can also arise [2]. 

The battle against cancer also relies on manipulating DNA replication. With no cure for this condition at present, scientists worldwide are now, more than ever, focused on researching DNA. It is said that cancer patients have “tumour-derived DNA fragments [circulating tumour DNA (ctDNA)]” and the discovery of these fragments has proven to be of value in assessing the spread and recurrence of cancer [3]. Epidemiology of COVID-19 can also be understood using DNA, particularly in the analysis of susceptible individuals. Successful viral entry and replication depend on the interaction of SARS-CoV-2 and the angiotensin-converting enzyme 2 (ACE2). Studies show that ACE2 gene polymorphism has an effect on the severity of COVID-19. It also has implications in individual susceptibility to the disease [4]. Genetic variation of ACE2, a direct result of DNA mutation, means different varieties of this enzyme will have different interactions with the virus, explaining why and how contracting the virus has different effects on people. 

While DNA studies are mainly seen in clinical settings, they are of use elsewhere: DNA has a longevity of several years, making it useful in historical tracing and archaeology. Such practical applications have helped history scholars learn where Richard III was buried, and also learn that Czar Nicholas II's children were killed during the Russian Revolution, disregarding speculations about their disappearance. Simple tracing of the unique DNA sequences allowed for such truths to be uncovered [5]. 

DNA can also be used in agriculture to identify crops as well as in “cloning of important agronomic trait genes, and molecular marker-assisted breeding” [6]. Applications of this can also be seen in the colours of biotechnology. Green biotechnology (for agriculture) sees its application in molecular engineering in plant selection to genetically modify plants with desirable traits [7, 8]. The concept behind the manufacturing of ‘golden rice’ uses DNA as the basis for such modifications, with the rice being genetically modified to increase vitamin A content. Although many controversies exist regarding consumption of  ‘golden rice’, it can be especially useful in helping reduce a widespread deficiency of vitamin A (retinol) in places such as Bangladesh, where 3,000 children die daily due to vitamin A deficiency [9]. 

DNA is versatile, having a wide spectrum of uses across various disciplines. The list of examples of its uses and applications is exhaustive, illustrating and demonstrating just how important it is, especially in modern biology. It is an undeniable fact that the discovery of DNA has positively impacted the world of science, assisting scientists on their quest to learn more about the genetics of various organisms. Such information has been beneficial in understanding epidemiology, ultimately improving our quality of life. 

References

[1] Khan Academy , "DNA structure and function," Khan Academy, 2020. [Online]. Available: https://www.khanacademy.org/test-prep/mcat/biomolecules/dna/a/dna-structure-and-function. [Accessed 5 July 2020].

[2] R. J. Aitken , G. N. De Iuliis and R. I. McLachlan, "Biological and clinical significance of DNA damage in the male germ line," International Journal of Andrology, no. 32, p. 48, 2008. 

[3] E. Heitzer, "Point: Circulating Tumor DNA for Modern Cancer Management," Clinical Chemistry , vol. 66, no. 1, p. 143, 2020. 

[4] C. A. Devaux, J.-M. Rolain and D. Raoult , "ACE2 receptor polymorphism: Susceptibility to SARS-CoV-2, hypertension, multi-organ failure, and COVID-19 disease outcome," Journal of Microbiology, Immunology and Infection, vol. 53, pp. 425-435, 2020. 

[5] J. Wilson, "CNN Health," Turner Broadcasting System , 25 April 2013. [Online]. Available: https://edition.cnn.com/2013/04/25/health/national-dna-day-tests/index.html. [Accessed 3 July 2020].

[6] C. Wang, X. Zhu, L. Shangguan and J. Fang, "Applications of DNA Technologies in Agriculture," Current Genomics, vol. 17, no. 4, pp. 379-386, 2016. 

[7] P. Kafarski, "Rainbow code of biotechnology," CHEMIK, vol. 66, no. 8, pp. 811-816, 2012. 

[8] M. C. S. Barcelos, F. B. Lupki, G. A. Campolina, D. L. Nelson and G. Molina, "The colors of biotechnology: general overview and developments of white, green and blue areas," FEMS Microbiology Letters, vol. 365, no. 21, p. 1, 2018. 

[9] Dhaka Tribune , "Bangladesh close to releasing Golden Rice," Dhaka Tribune, 28 October 2019. [Online]. Available: https://www.dhakatribune.com/bangladesh/agriculture/2019/10/28/bangladesh-close-to-releasing-golden-rice. [Accessed 13 July 2020].