Synthetic Biology: Innovation or Mad Science?

   

The four bases that make up DNA may not be the only ones with the ability to support life.
Courtesy: http://plus.maths.org/content/dna

           Every introductory course in biology teaches students about the building blocks of deoxyribonucleic acid, or DNA. DNA holds the key to life because it holds the instructions needed to make proteins, which facilitate and carry out chemical reactions necessary for life. DNA is composed of units called nucleotides, which consist of three phosphate groups, a 5-carbon sugar, and a nitrogen-containing base. Four nitrogen-containing bases comprise the genetic code: adenine, guanine, cytosine, and thymine. These bases pair with each other, adenine to thymine (A-T) and guanine to cytosine (G-C), to form the characteristic double helix structure of the DNA molecule. These bases have remain fixed for the entire course of evolution, meaning no additional bases have been found in any existing organism. Due to this observation, scientists have been in concordance that only these four bases can support life.

          However, this long-standing dogma may not necessarily be true. A recent report in Nature describes the generation of Escherichia coli (E. coli) cells that carry a third pair of bases in its DNA. Romesburg and colleagues at the Scripps Research Institute in La Jolla, California, have incorporated an unnatural base pair that can be replicated effectively in bacterial cells without compromising their growth. The Romesburg group utilized two compounds, d5SICS and dNaM, to form a new pair of bases, and they were able to introduce these bases into E. coli cells by expressing a gene that encodes a special nucleotide transporter found in algae. Once these synthetic bases were in bacterial cells, they were observed to contribute to the propagation of a plasmid (a circular piece of DNA) containing the unnatural base pair formed by d5SICS and dNaM. Bacteria carrying this modified plasmid were able to divide normally, suggesting that the introduction of the d5SICS and dNaM base pair was not toxic to bacterial cells. These results indicated to the Romesburg group that it was possible to introduce an unnatural nucleotide base pair into an organism without deleterious effects.

          This newest breakthrough in the field of synthetic biology is a step forward for scientists looking to re-engineer cells for various purposes. Some researchers have praised this study as a stepping stone for one day enabling cells to produce biofuels or medicines that have been historically expensive to produce. It is the hope that one day scientists will be able to produce environmentally safe energy alternatives and other necessary products from organisms, eliminating the need to spend millions to obtain these materials utilizing conventional methods.

          On the other hand, another faction believes that these studies may be used for malicious or unnecessary purposes. Some people believe that scientists are going too far in creating organisms that produce substances that they would not normally produce. In their eyes, scientists are "trying to play God" and are engaging in "mad science." However, these individuals often forget that scientists are far removed from re-engineering animals, or even humans, with foreign DNA, and that many ethical safeguards exist to prevent the misuse and abuse of these new technologies. The aim of synthetic biology is not to employ animals and humans as guinea pigs for radical experiments, but the aim is to formulate novel methods for generating biological materials that are scarce or costly to manufacture. This newest advancement in the synthetic biology field should make this goal more attainable in the near future.