By: Elida Met-Hoxha
Bacteria and viruses have raged war against each other since the beginning of life. A phage, or virus, will insert its DNA into bacteria and essentially make them little virus factories that produce viral DNA until they lyse and release more phages into the environment. However, there are bacteria that survive these invasions. In fact, many bacterial cells contain an adaptable immune system which allows them to effectively detect any viral DNA in their system before any damage can occur. Part of the immune system is CRISPR, a DNA archive passed on to progeny. When a bacterium survives a viral, or bacteriophage attack, it saves a part of the viral DNA in this archive so that it can recognize and act when attacked by the same type of phage. There is a protein called Cas9 that will essentially look through the bacterium’s DNA until it discovers viral DNA in the chromosome. Cas9 then activates and makes a double-stranded break (DSB) to cut out the viral DNA. Since the cell has its own mechanisms for repairing DSBs, when the complex is programmed to make a site-specific DSB, then this technology can be used to insert and delete very specific parts of genetic material into cells.
While gene-editing tools have been around for decades, the CRISPR technology is more precise in its editing, efficient, and cost-effective. I remember I must have been about 11 or 12 when I first heard about the CRISPR technology. I was sitting in a hospital waiting room, reading this article in Time, and I was doubly excited and terrified. The talk of future alteration of the entire human genome and designer babies scared me, and I remember wondering if I would even have been allowed to exist in such a world, or perhaps how different I would be. To be honest though, I was more fascinated than anything. Such a tool could not only create treatment therapies for a wide range of diseases, but it could also help shed light on so many different biological processes. Especially now, the CRISPR technology can yield great insight on the functions and roles of different types of genes, especially in relation to anthropogenic stressors and climate change.
Coral reefs, the most biodiverse and climate-sensitive ecosystem in the world, have been particularly impacted by these stressors. According to NOAA, coral reefs sustain about 25% of all the ocean’s fish and contribute to the livelihoods of over half a billion people. They also protect from severe storms and currents by acting as a buffer for waves. And yet, according to the IPCC, a 1.5C rise in global temperatures would see a 70-90% decline of coral reefs by the end of the century, whereas a 2C increase would lead to a 99% loss.
Whereas researchers previously lacked the tools necessary to better understand coral biology to head conservation efforts, CRISPR allows them the capability to identify what genes are involved in coral bleaching or how best to safeguard against it. Recently, researchers from Stanford University examined over 500 genes which may be involved in coral reaction to heat stress using CRISPR. Their findings suggested that certain genes could trigger bleaching, and when they targeted a gene in the coral called HSF1, they found the coral’s ability to survive in warmer waters greatly diminished.
Coral reefs are just one example. Where knowledge was previously limited, CRISPR is allowing for greater observation and understanding. The fact is, no matter what climate mitigation efforts are taken now, the Earth will continue to warm. If we understand more about ecosystems and biological reactions to abiotic stressors, however, it will allow a greater understanding of fragile habitats which will help lead conservation efforts.
CRISPR has also already been effectively used to bioengineer crops better equipped to handle abiotic stressors. For instance, researchers at the Spring Harbor Laboratory made small alterations to tomato traits to produce variation in the plant, allowing for an improved tomato shape and size (read the research). Additionally, researchers have been able to target a gene in rice which inhibits its resistance to Blast disease, a fungal infection exacerbated by climate change, drastically reducing rice output each year (read the research). Others are working on engineering a rice crop better able to exist in warmer climates. The engineered crops could ensure that growing food demands are met and that plants can survive in what will inevitably become inhospitable regions.
To achieve a more sustainable future, we must stop trying to engineer our ways out of problems. Prevention is always better than treatment, and problems are not fixed by introducing new ones. In this sense, the role of biotechnologies when it comes to climate change mitigation should be more to demystify biological processes, to head conservation efforts, or to produce modifications when necessary. This must be an approach in wonder, not exploitation, in aid, not consumerism. The use of innovation to combat climate change must be sustainable. I remember reading about the irony of having solar panels atop a Walmart, and the same logic is applied here. CRISPR can teach us so much about our surroundings, and we can in turn create nature-driven solutions, but if such a powerful gene-editing technology instead becomes a tool to appease consumerist frenzy, then it is no longer sustainable. Then it engenders divisiveness. Environmental justice is much more encompassing than it seems. It is not just about surviving climate change. It is a combination of things, which includes equity and social justice. Keeping those things in mind, CRISPR can tell us more about the extremely captivating ways nature works, and perhaps, with prudence and ecological consciousness, this knowledge can help us combat food insecurity and preserve so many wonderful habitats around the world.
Works Cited and Other Suggested Readings
- Bacteria may contribute more to climate change as planet heats up. (2019, November 12). Retrieved December 07, 2020, from https://www.sciencedaily.com/releases/2019/11/191112110214.htm
- Butt, H., Eid, A., Momin, A.A. et al. CRISPR directed evolution of the spliceosome for resistance to splicing inhibitors. Genome Biol 20, 73 (2019). https://doi.org/10.1186/s13059-019-1680-9
- Cleves, P. A., Krediet, C. J., Lehnert, E. M., Onishi, M., & Pringle, J. R. (2020). Insights into coral bleaching under heat stress from analysis of gene expression in a sea anemone model system. Proceedings of the National Academy of Sciences, 117(46), 28906-28917. doi:10.1073/pnas.2015737117
- Cleves, P. A., Tinoco, A. I., Bradford, J., Perrin, D., Bay, L. K., & Pringle, J. R. (2020). Reduced thermal tolerance in a coral carrying CRISPR-induced mutations in the gene for a heat-shock transcription factor. Proceedings of the National Academy of Sciences, 117(46), 28899-28905. doi:10.1073/pnas.1920779117
- Coral Reefs. (n.d.). Retrieved December 07, 2020, from https://coast.noaa.gov/states/fast-facts/coral-reefs.html
- Doudna, Jennifer. “How CRISPR Lets Us Edit Our DNA.” TED, www.ted.com/talks/jennifer_doudna_how_crispr_lets_us_edit_our_dna?language=en.
- Handler, Mauricio. Chrinoid and a Soft Coral Tree Decorate the Edge of a Coral Reef (Photo). www-bridgemaneducation-com.
- Haque, E., Taniguchi, H., Hassan, M. M., Bhowmik, P., Karim, M. R., Śmiech, M., . . . Islam, T. (2018). Application of CRISPR/Cas9 Genome Editing Technology for the Improvement of Crops Cultivated in Tropical Climates: Recent Progress, Prospects, and Challenges. Frontiers in Plant Science, 9. doi:10.3389/fpls.2018.00617
- Jones, J. D., Witek, K., Verweij, W., Jupe, F., Cooke, D., Dorling, S., et al. (2014). Elevating crop disease resistance with cloned genes. Philos. Trans. R. Soc. Lond. B Biol. Sci. 369:20130087. doi: 10.1098/rstb.2013.0087
- Nayak, D., Dipti and Metclaf, W., William(2017). Cas9-mediated genome editing in the methanogenic archaeon Methanosarcina acetivorans. Proceedings of the National Academy of Sciences, 114(11), 2976-2981. doi:10.1073/pnas.1618596114
- Productions, Atlantic. An Interactive Journey. attenboroughsreef.com/.
- Rodríguez-Leal, D., Lemmon, Z. H., Man, J., Bartlett, M. E., and Lippman, Z. B. (2017). Engineering quantitative trait variation for crop improvement by genome editing. Cell 171, 470–480.e8. doi: 10.1016/j.cell.2017.08.030
- Summary for Policymakers of IPCC Special Report on Global Warming of 1.5°C approved by governments. (n.d.). Retrieved December 07, 2020, from https://www.ipcc.ch/2018/10/08/summary-for-policymakers-of-ipcc-special-report-on-global-warming-of-1-5c-approved-by-governments/
- Wang, F., Wang, C., Liu, P., Lei, C., Hao, W., Gao, Y., et al. (2016). Enhanced rice blast resistance by CRISPR/Cas9-targeted mutagenesis of the ERF transcription factor gene OsERF922. PLoS ONE 11:0154027. doi: 10.1371/journal.pone.0154027