REVEALING THE GENETIC CODE: HOW GENETIC ENGINEERING HAS TRANSFORMED LIFE ON EARTH?
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INTRODUCTION
In 1944, the ground-breaking discovery of DNA as the hereditary genetic materials (Avery, Macleod, & McCarty, 1944) had acted as the catalyst, accelerating the development of nucleic acid technological advancements within molecular biology. The researchers began editing DNA using highly specialized enzymes, such as DNA ligases and endonucleases by the early 1970s (Cohen et al., 1973; Jackson, Symons & Berg, 1972). Both studies were the earliest experiment in manipulating DNA with the use of recombinant DNA technology. Generally, genetic engineering, also known as recombinant DNA technology, refers to all the techniques utilized to artificially edit the genetic materials, chiefly DNA substance of an organism in order to alter and enhance the preexisting cellular functions or repair the damaged genetic materials (Pyne, Sukhija & Chou, 2011; Robert & Baylis, 2008; Rosenberg, 2017). Many types of genetic editing can be made to manipulate DNA, including knockins, knockouts and substitution of exogenous sequences for natural DNA sequences (Lanigan, & Saunders, 2020; Pyne, Sukhija & Chou, 2011). The process of gene inactivation, whereby the gene’s function is lost due to disruption by either insertion or deletion of its open reading frame (ORF), is known as a gene knockout (Pyne, Sukhija & Chou, 2011). Any disruption within the gene sequences is likely to generate a nonfunctional protein by changing protein coding sequence (Xiong et al., 2018) or deactivate gene expression by removing regulatory region within the genome (Allan et al., 2019). The process of new genetic information insertion, whereby a variety of genetic elements can be inserted within the genome without knocking out the targeted gene (can Hummel et al., 2016; Yang et al., 2013; Gu, Posfai & Rossant, 2018). For example, knockins of epitope tags on protein can be used to detect antibodies in vivo (Su et al., 2017). Besides, the substitution of DNA sequences within the genome will block gene function and activate the functionality of a newly inserted gene simultaneously, such as lacZ gene (Lai et al., 2015). These technological advancements have exhibited rapid progression, specifically, on the domain of environmental management.
ENVIRONMENTAL MANAGEMENT
The breakthrough of GE bacteria like Pseudomonas putida demonstrates humans’ ability to modify bacteria to mitigate oil spill by breaking down multiple components of petroleum (Chakrabarty, 2010). Furthermore, the production of bioplastics and biofuels facilitated by GE bacteria, reflects our increasing ability to generate environmentally friendly substitutes, thereby reshaping our perspective on the resource use (Pandey et al., 2010; Lin et al., 2013). For instance, the genetic engineering of the cyanobacterium Synechocystis sp. PCC6803 has resulted in the increased synthesis of bioplastic polyhydroxy butyrate. This advancement has been achieved by the overexpression of two key proteins, SigE and Rre37 (Osanai et al., 2014). In the context of biodiversity, GE also provides a unique method to adapt and even save animal species facing extinction. The concept of facilitated adaptation, which involves the transfer of gene variants from a well-adapted population to threatened populations that possess the risk of extinction, either within the same species or distinct species, has been proposed to address maladaptation and prevent extinction (Thomas et al., 2013), entailing the active intervention of humans to safeguard the survival of species, thereby representing a morally progressive growth in our responsibility as caretakers of the Earth. Additionally, GE has widely utilised in the ares of phytoremediation and plant metabolism development (Khan et al., 2016). This approach has been effectively employed in the detection and absorption of contaminants, specifically in drinking water. For example, the incorporation of the AtPHR1 gene into various garden plants such as Verbena, Petunia and
Torenia has resulted in their increased phosphorus absorption capabilities, possiblyfacilitating efficient phytoremediation of polluted aquatic environments (Matsui et al., 2013). It is noteworthy that although AtPHR1 has proven effective across several plant species, the overexpression of this gene may impede the posttranscriptional alteration of the endogenous AtPHR1 homologue (Matsui et al., 2013). Moreover, the modification of plant metabolism processes has proven significant for remediating environmental pollutants that are resistant to digestion or degradation. An example of genetic modification involves the knockout of the gene responsible for monodehydroascorbate reductase, leading to enhanced plant tolerance against the explosive compound TNT. The generation of hazardous superoxide due to incomplete degradation of TNT can be prevented via this knockout engineering (Jez, Lee & Sherp, 2016). GE has also improved arsenic tolerance of plants as arsenite is the serious soil contaminants by introducing a key arsenite antiporter gene, PvACR3 in Arabidopsis plants. The transgenic plants demonstrated remarkable tolerance to arsenic particles, allowing them to germinate and grow in arsenic-rich conditions lethal to their wild-type counterparts (Clemens & Ma, 2016). Another application of GE in environmental management is energy applications. One notable application is the use of microorganisms, specifically cyanobacteria, for hydrogen production as an ecofriendly energy source. GE have been employed to optimize hydrogen production via alteration of activity of specific enzymes in cyanobacteria (Ullah et al., 2015). The commercialization of hydrogen can protect our environment from the detrimental impacts commonly associated with the conventional energy sources that emit carbon dioxide (CO2) and other pollutants (Tiwari & Pandey, 2012). Moreover, cyanobacteria can be genetically modified to convert CO2 into reduced fuel compounds as CO2 is a major greenhouse gas. This approach renders carbon-based energy application less environmental harm due to the reduction of carbon emissions (Savakis & Hellingwerf, 2015). In addition to hydrogen production and reduction in carbon dioxide reduction, the application of GE also extends to the manipulation of other microorganisms, such as Geobacter sulfurreducens. Geobacter sulfurreducens possess the ability to form conductive biofilms, promising potential use in bioelectronics, renewable energy, and bioremediation. Through genetic engineering, such as targeted knockout of specific genes such as PilZ genes in Geobacter sulfurreducens, conductivity and biofilm activity can be improved, increasing the potential energy by lowering losses (Leang et al., 2013). By introducing new functionalities or enhancing plants’ natural capabilities, the synergy between genetic engineering and environmental management has redefined our approach to pollution control and ecological sustainability.
The application of GE in environmental management and its associated ethical dilemmas deserve attention. In the development of energy production, both opportunities and challenges have also raised important ethical concerns that need careful consideration. One ethical issue related to energy applications of GE involves the possibility of unforeseen ecological consequences. GE can be utilised to alter the genetic contents of microorganisms to generate more environmentally friendly biofuels and remove environmental pollutants. Although unintentional release of GE microorganism is less likely to happen since numerous measures have been performed to produce bacteria that are incapable of surviving outside of specific laboratory conditions, a risk of accidental release of these genetically modified microorganisms into the environmental could occur, leading to unintended ecological disturbances. Such accidents have happened for non-genetically engineered microorganism in the past. For example, the spread of tobacco blue mould Peronospora hyoscyami f.sp. across Europe has taken place (Lucassen, 1996). This could potentially compromise biodiversity and ecosystem integrity with unpredictable and far-reaching consequences. Thus, the use of GE microorganisms must be accompanied by proper safety regulations and laboratory policies until the long-term consequences of the natural ecosystem are betterunderstood (Ormandy, Dale & Griffin, 2011). Furthermore, energy application using GE microorganisms might also lead to genetic drift and contamination. Genetic drift refers to the alteration in allele frequencies within a population as a result of random sampling events such as variations in survival that are not linked to an individual’s genotype or phenotype (Hays & Fagan, 2016). If the GE microorganism outcompetes native species, the introduced genetic characteristic of GE microorganism might spread rapidly through the population, leading to the changes in the allele frequencies. For instance, an GE microorganism designed to digest pollutants might impact the balance of ecosystem. The potential disruption of ecosystem may also arise from the unanticipated interactions between GE microorganisms and native species (Ormandy, Dale & Griffin, 2011). Hence, the ethical assessment and risk assessment prior to the widespread use of GE microorganism are essential to safeguard the biodiversity and maintain ecosystem stability.
CONCLUSION
In conclusion, genetic engineering has marked a transformative era where human holds the capability to modify the genetic composition of living creatures, with signification implications in different areas. Across these fields, ethical, regulatory, and social considerations are the major challenges in genetic engineering. Hence, achieving a harmonious equilibrium between the advantages of GE and its potential risk requires a well-planned and comprehensive regulatory framework that considers the equity, accessibility and potential misconduct of GE to define the boundaries of humanity’s relationship with this transformative technology.
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This article was prepared by Lam Zhi Xin (Bachelor of Biomedical Sciences, Universiti Malaya).
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