The advent of genetic engineering brings with it a plethora of prospective benefits as well as ethical concerns. In this article, we will be analyzing the advantages of furthering research and development in the field.
Written by Shreya
Genetic engineering offers the potential to revolutionize healthcare, agriculture, climate change alleviation, and medicine. Editing other species’ and our own genomes can yield new medicinal drugs and hormones, more hardy crops, decreased pesticide use, and much more, benefiting not only humanity but the entire global ecosystem. As a quick refresher, genetic engineering is the direct alteration of DNA using technology– often in order to introduce a foreign gene into the base organism. This allows scientists to engender a transgenic organism that expresses specific, desired traits. Let’s take a look at some of the current and prospective applications of genetic engineering in modern society.
Agriculture
Currently, there are 10 genetically engineered varieties of crops used in the United States with over 120 seed varieties deregulated for production, growth, and consumption. Of these crops, GMO corn, canola, sugar beet, cotton, and soybean are the most prevalent with more than 90% of each being genetically engineered (1). Genome editing allows farmers to work with crops that are insect resistant, provide easier weed control, improve nutritional value, require less water, and/or undergo enzymatic browning (rotting) less quickly. For instance, the first engineered crop to be introduced to the market was the FLAVR-SAVR tomato of 1994. Tomatoes have an extremely short shelf life and go soft quickly after harvest. Transporting ripe crops often led to damaged and rotting fruit by the time the produce reached the market. As a solution, farmers harvested the tomatoes when they were green, and a few days before they reached the market, the tomatoes were sprayed with ethylene gas, which prompts ripening. However, inducing the ripening stage was mainly for aesthetic purposes; it did not assist in developing the tomato’s flavor, which would only result from the natural growing process of the fruit. In response to this dilemma, the company Calgene produced genetically engineered tomatoes that were modified with a gene that decreases the production of polygalacturonase– an enzyme that degrades cell walls and softens fruit (2), yielding a tomato with a longer shelf life. Current crop varieties contain similar gene variants in addition to pest resistance genes (such as the Bt gene we looked at in the last article), nutritional value genes, and drought tolerance genes (3), enabling more organically grown produce, higher vitamin and antioxidant content in our food, greater profits for farmers, and crops that can withstand rising temperatures.
Current researchers are also looking into engineering plants that can use atmospheric nitrogen or fixate their own nitrogen. Atmospheric nitrogen is present in the form of nitrogen gas, or N2, while plants can only use nitrate (NO3-) and ammonium (NH4+) to generate proteins and chlorophyll. Many plants develop mutualistic relationships with bacteria and fungi in their roots that can fixate atmospheric nitrogen into a usable form, but in agricultural environments, heavy doses of nitrogen fertilizer are used instead. Synthetic fertilizers, while cheap and effective, can cause devastating consequences for the environment, such as eutrophication (the death of a water body ecosystem), water contamination, and acid rain. To mitigate this issue, scientists are looking into the nitrogen-fixating gene of the Klebsiella bacterium in the hopes of being able to engineer it into crop species, which could render crops that do not require any nitrogen fertilizer (3). This would not only decrease contamination in the local environment but also decrease fossil fuel consumption from the production and transportation of fertilizers, which combined yields 0.8% of greenhouse gas emissions per year (4).
Plants can intake ammonium or nitrates from nitrogen-fixing bacteria that live in the soil or from synthetically produced fertilizers.
Climate Change
Genetic engineering could also potentially enable us to slow down or even reverse climate change. By generating crops that have a higher nutritional value, are less susceptible to disease, and rot less easily, farmers are able to produce more food on less land. Land clearance for agriculture is one of the leading causes for climate change due to fossil fuel use for deforestation and the release of sequestered carbon when removing biomass. Vegetation and soil act as carbon sinks, storing carbon from photosynthesis in both live and dead organic matter. However, when forests are cleared to make space for farmland, this carbon is released back into the atmosphere in the form of carbon dioxide and carbon monoxide- two greenhouse gases that contribute towards global warming (5).
In addition, researchers are looking into engineering plants to become “capture plants” that sequester substantial amounts of carbon dioxide from the atmosphere in order to reverse climate change. The American chestnut tree is a sponge for atmospheric carbon, absorbing more carbon dioxide than almost any other species of trees. If labs are able to produce hybrid plants that carry the heavy carbon sequestration trait from this chestnut variety, they can potentially establish powerful carbon sinks that absorb more carbon dioxide than we currently produce. Worldwide, trees absorb ⅙ of the carbon emissions produced annually; with these hybrid varieties, that value could rocket upwards. Furthermore, the vast majority of the American chestnut tree population was wiped out by a fungal blight about a century ago, but with the blight resistance gene from the Chinese chestnut tree, its population could be brought back up (6).
Greenhouse gases like carbon dioxide prevent heat that is reflected from the surface of the earth from escaping into space; rather, they trap heat in the atmosphere, which contributes towards global warming.
Medicine
There are over 10,000 disorders and diseases that genetic engineering tools such as CRISPR could cure, including cancer, Huntington’s, cystic fibrosis, HIV, muscular dystrophy, and color blindness. By replacing aberrant gene sequences with their normal precursors, future doctors could correct genetic defects.
A study on HIV done on mice in 2019 showed that CRISPR can assist in ridding the body of HIV, a virus that patients are currently afflicted with for life. As of now, patients are treated with antiretroviral drugs that slow the proliferation of the virus in the body but are unable to completely eliminate its presence. When the drug was coupled with the removal of the HIV sequence from the genome by CRISPR gene editing, 9 out of the 23 mice used in the experiment were virus-free after 8 weeks of treatment. Although this method of treatment will need immense refinement before being marketed for human use, it provides proof of concept that the total elimination of the virus is feasible through genetic engineering (7). Scientists in China also used CRISPR to engineer HIV immunity into stem cells; these cells were then transplanted into an HIV-positive adult male. The resistant cells were able to survive in the patient for over a year, leading scientists to believe that transplanting a much larger quantity of engineered stem cells could limit the virus’s access to nutrients and decrease the amount of HIV in the body (8). CRISPR can also help discover drug targets. Many disorders stem from improper gene transcription and regulation, and CRISPR can essentially turn these genes “on” or “off” by correcting them.
The Trade-off
While genetic engineering presents a multitude of potential benefits to society, its use must be heavily regulated and confined to ethical boundaries. In the next article, we will take a look at the potential harms and concerns that arise when we take the innate genetics of humanity and other species into our own hands.
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