By Isha Verma
To have a fundamental understanding of genetics, it is important to recognize that the basis of genomic structures depend on the makeup of nucleic acids. Nucleic acids create crucial molecules called nucleotides, which are chemical structures consisting of a phosphate group, pentose sugar and a nitrogenous base. These complexes are what make up genetic structures in our bodies such as DNA and RNA, which have the ability to carry essential genetic information in order to compose a range of organisms. This is done through processes such as transcription, producing RNA from DNA, and translation, producing a protein from RNA. For years, nitrogenous bases have acted as the letters to the genetic alphabet for all living organisms, and scientists believed that these biological structures composed of four main nitrogenous bases in DNA (adenine, guanine, cytosine and thymine) and a different set in RNA (adenine, guanine, cytosine and uracil). However, two new, unnatural nitrogenous bases have been recently discovered through engineering a new type of bacterium through an in vitro study, done in test tubes. In an attempt to build the genetic code, this research began when scientists manipulated the Escherichia coli bacterium to include two artificial nitrogenous bases - X and Y - into its DNA (Guglielmi, 2017).
The scientific names given to these bases, reflecting its chemical makeup, are “d5SICS” and “dNaM”. Known as the “alien” pair of bases, these complexes were added into the genes of the E. coli bacteria along with the four traditional nitrogenous bases. Interestingly, genetic molecules were able to recognize these bases, and continue the process of transcription by creating a new RNA sequence, even though the alien pair of bases were present. Through this discovery, scientists predict that since the traditional four DNA bases can code for 20 amino acids, the addition of X and Y could produce up to 172 amino acids (Weiner-Bronner, 2014). With the creation of new amino acid combinations which are not already found in nature, this new pair of bases may become the new building blocks of chemical structures which make up new drugs and materials. For example, some researchers are currently investigating the potential uses of this technology when applied to cancer cells. This includes the incorporation of a toxic amino acid into a protein and tracking its biological reactions when exposed to cancerous structures (Anthony, 2014). With an application to healthcare, these new combinations may be able to research new methods of pharmacological treatment for a range of diseases in the future, revolutionizing the ways which medicine can make a positive impact on lives around the world.
References
Anthony, S. (2014, May 16). First living thing with 'alien' DNA created in the lab: We are now
officially playing God. Retrieved from
Callaway, E. (2014, May 7). First life with 'alien' DNA. Retrieved from
Guglielmi, G. (2017, November 29). Scientists just added two functional letters to the genetic
code. Retrieved from https://www.sciencemag.org/news/2017/11/scientists-just-added-two-functional-letters-genetic-code
Wiener-Bronner, D. (2014, May 07). Scientists Successfully Expand the Genetic Alphabet.
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