Genetically-Modified Organisms: The good, the bad, and the future

Image by Hannah Somheygi.

The Nobel Prize is named after a scientist, Alfred Nobel, who established the prizes in his will in 1885. Alfred Nobel is famous for inventing dynamite. However, he mistakenly believed that his invention would bring about a more peaceful world. He is quoted as saying, “My dynamite will sooner lead to peace than a thousand world conventions. As soon as men will find that in one instant, whole armies can be utterly destroyed, they surely will abide by golden peace” [1]. In fact, his invention led to the development of many modern tools of war.

Dynamite is a technological advancement that led to the deaths of many people. However, technological advancements have not exclusively made the world a worse place. Because of technological advancements, more people than ever before have access to tools that make life easier such as medicine, electricity, and indoor plumbing. Genetically-modified organisms (GMOs) are some of the more recent and controversial tools that have been developed. According to the companies and scientists who design new GMO crops, this new technology is harmless to humans, better for the environment, and is the only way to feed an ever-growing population [2]. On the other hand, anti-GMO groups claim that GMOs cause health problems for both humans and animals, destroy the environment, and only benefit large corporations. So, why did scientists develop these new organisms?

Crop scientists and engineers want to come up with solutions to problems facing the world, like decreased yields due to pests and weeds. For example, Roundup Ready corn was supposed to be better for the environment by decreasing the amount of herbicide farmers needed to use on their crops. Scientists also make GMOs to address health problems in the developing world. For instance, Golden Rice was developed to prevent Vitamin-A deficiency in the children of developing countries. In both of these examples, the scientists had a socially-responsible motive for creating a GMO. However, it can be difficult to predict all the effects (both good and bad) of a new technological advancement. In order to decide for ourselves what the effects of GMO use have been, we need to look at the most unbiased source of information—the scientific literature.

Herbicide-resistant corn

Herbicides are chemicals, often highly toxic, that are sprayed on weeds in order to kill them so that they do not compete with the desired crop for space and nutrients. Some are selective for certain kinds of plants. Others, including Roundup, are nonselective, and if they are sprayed on both weeds and crops, they will kill both. Scientists thought that if the crops were resistant to Roundup, use of the herbicide would be more effective. Spraying the whole field with Roundup would take less time and actually use less Roundup than spraying the weeds one by one. Using less herbicide in this way would be better for the environment as well. For these reasons, Roundup Ready corn and soybeans were created to be resistant to Roundup.

The chemical in Roundup that kills plants is called glyphosate. Glyphosate works by inhibiting the plant enzyme that helps make some of the amino acids (protein building blocks) that the plant needs to survive [3]. Roundup Ready crops contain a different version of this enzyme that is not blocked by glyphosate. Use of glyphosate-resistant crops was supposed to decrease herbicide use because less herbicide would be needed to kill the weeds, and to some extent, it has. Based on national pesticide usage data and other previously published pesticide use data from a number a sources in the scientific literature, it seems that herbicide use has decreased. From 1996 to 2011, use of herbicide-tolerant cotton reduced herbicide use by 6.1% compared to conventional cotton [4]. However, the liberal use of herbicides by farmers who grow herbicide-resistant crops has catalyzed the evolution of herbicide-resistant weeds. Since Roundup Ready crops were introduced in 1996, at least sixty-four weed species have evolved resistance [5]. Because of herbicide-resistant weeds, farmers will now have to increase herbicide use, so the recent decreases will not last. From these experiences, scientists have learned that engineering plants to be resistant to herbicides is not an effective long-term solution.

Baby steps towards Golden Rice

There is always room for improvement when new technologies are introduced, and GMOs are no different. Science is an iterative process that results in sequential improvements as a greater understanding of the problem is obtained and as better technologies are developed. Golden Rice is a strain of rice which contains a set of genes which allows it to make β-Carotene – the chemical that makes carrots orange and is turned into Vitamin A inside the body. The genes in Golden Rice that make β-Carotene come from other plants that naturally make it, like daffodils and corn. Golden Rice was developed to help combat Vitamin A deficiency problems in developing countries where diets are low in foods containing Vitamin A. Vitamin A deficiency is especially dangerous for children and pregnant mothers and commonly leads to blindness and even death [6]. Currently, Vitamin A deficiency can be prevented by taking oil-based supplements provided by international organizations, but Golden Rice may be even better at relieving Vitamin A deficiency because rice is a staple food in many countries, and it can be difficult to convince children to take vitamin supplements.

In the first iteration of Golden Rice, children would have had to eat several kilograms (up to 10 pounds!) of rice per day to get their recommended daily value of Vitamin A [7]. Therefore, scientists re-designed and improved the rice by switching out one of the genes that came from daffodils and instead put in a related one that came from corn. According to the scientific literature, the gene from corn worked much better, and the rice contained 23 times as much Vitamin A as the earlier version [8]. The scientists also showed that the rice was as good a source of Vitamin A as β-Carotene-filled oil capsules, which contain about the recommended daily value’s worth of β-carotene for a child [9]. They did this by taking blood samples from children who had consumed either the rice or the capsules, and looked to see how much of their β-Carotene had been converted in to Vitamin A. They found that the β-Carotene in Golden Rice was converted in to Vitamin A just as well as it was for the oil capsules. Despite these promising results, a remaining concern with Golden Rice is that Vitamin A content of the rice could decrease after it has been stored a long time. There have been no studies on this yet, but you can bet that there are scientists working on it right now.

The future?

Without a doubt, technological innovations can lead to advancements that may do more harm than good. This is why rational debate based on unbiased scientific data in the literature is essential. By questioning every aspect of a new technology, possible downsides can be uncovered, and strategies for improvements can be planned. When it comes to GMOs, there are many aspects that can be improved. However, many experts believe that if the human population continues to grow, current methods of farming will not feed everyone [2]. As the author and scientist Sam Harris has said, “If questions affect human wellbeing, they have answers” [10]. Scientists are always looking for these answers. When the public is educated on the problems the world faces, and supports research that aims to create socially-responsible solutions, scientists can work to make the world a better place.
 

Written by Marina Santiago

References:

[1] Charlton, James.  (2002) The Military Quotation Book. P114 en.wikipedia.org/wiki/Alfred_Nobel

[2] Chen, Chi-Chung and Wei-Chun Tseng (2011) Do Humans Need GMOs? – A View from a Global Trade Market. Journal of American Academy of Business 8(1): 147.

[3] Steinrucken, H.C. and N. Amrhein. (1980) The herbicide glyphosate is a potent inhibitor of 5-enolpyruvylshikimic acid-3-phosphate synthase. Biochemical and Biophysical Research Communications 94(4): 1207-1212

[4] Brookes, Graham and Peter Barfoot. (2013) Key environmental impacts of global genetically modified (GM) crop use 1996-2011. Landes Bioscience 4(2): 109-119.

[5] Heap, Ian. (2013) International Survey of Herbicide Resistant Weeds. www.weedscience.org/GRAPHS/SOAGRAPH.aspx

[6] (2013) Micronutrient Deficiencies: Vitamin A Deficiency. Nutrition. World Health Organization. www.who.int/nutrition/topics/vad/en/index.html

[7] Coghlan, Andy (2013) Is Opposition to Golden Rice “Wicked”? Slate. http://www.slate.com/articles/health_and_science/new_scientist/2013/10/golden_rice_inventor_ingo_potrykus_greenpeace_and_others_wicked_for_opposition.html

[8] Coghlan, Andy. (2005) New ‘golden rice’ carries far more vitamin. New Scientist. www.newscientist.com/article/dn7196-new-golden-rice-carries-far-more-vitamin.html

[9] Tang, Guangweng et al. (2012) β-Carotene in Golden Rice is as good as β-carotene in oil at providing vitamin A to children. The American Journal of Clinical Nutrition 96(3): 658-664.

[10] Harris Sam, (2010) Science can answer moral questions. Ted Talk. www.ted.com/talks/sam_harris_science_can_show_what_s_right.html