Scientists are constantly striving to make what was once thought of as impossible, possible. But, often in this race to break barriers, what holds back the scientific community is the ethical implications of their actions. With new gene-editing technology, such as CRISPR-Cas9 and TALENs, becoming well-known and easily accessible, genetic alterations are no longer an impossibility. The introduction of these methods presents untold opportunities for genome modification in plants, animals and even humans. However, while there are many positive applications for this new technology, there are also serious ethical ramifications that arise because of this newfound ability. This essay will define what CRISPR-Cas9 and TALENs are, explain current Australian law on the use of this technology and analyse positive and negative ethical arguments for and against its use, in order to determine if Australia should allow this new technology to be used to its full potential.
What is CRISPR-Cas9?
CRISPR-Cas9 or clustered regularly interspaced short palindromic repeats, is a genome editing system originally found in bacterial immune systems when responding to viral invaders (2019, May 28). When found in bacteria, this immune system response begins by creating spacers, segments of viral DNA, within the CRISPR arrangement (n/d). Once the spacers have been included into CRISPR, transcription occurs and the RNA produced is then cut into small pieces, referred to as CRISPR RNA’s (n/d). These CRISPR RNA’s act as a guide for the targeted destruction of the viral DNA by enzymes such as Cas9 (n/d) (Refer to figure 1 in appendix for diagram of CRISPR response in bacteria). When this is recreated in laboratories, the CRISPR RNA’s are instead designed by scientists to ensure that the correct complementary strand is created for the targeted sequence (2019, May 28). Like when in bacteria, these CRISPR RNA’s are guides that attach to the targeted sequence and direct the enzyme (usually Cas9) to the site (2019, May 28). The Cas9 enzyme then cuts this segment from the arrangement, effectively removing the unwanted section (2019, May 28). The ‘space’ that results from the cut can either be filled by a synthetic template or be re-connected without a new inclusion through DNA repair mechanisms (2016, December 19) (Refer to Figure 2 for Diagram).
What is TALENs?
Transcription Activator-Like Effector Nucleases more commonly referred to by its abbreviated form TALENs, are synthetic enzymes created to cut DNA at targeted regions (2019, February 26). These synthetic enzymes are created by combining a transcription activator-like effector (TALE) with a nuclease (DNA cleavage domain) (2019, May 5). Much like CRISPR, TALEs are originally found in bacteria. They are a protein secretion produced by Xanthomonas bacteria upon infecting a plant (2019, May 6). Once within a plant TALEs bind to promoter sequences, which they identify through a central repeat domain, to stimulate genes that will further promote the bacterial infection (2019, May 6). The domain that is often used to create this module is Fok1 and upon connecting to a TALE this allows for the DNA strand to be cleaved at the targeted location (2018, October 31).