GMOS: Technology as nature-killer?

Basics of Genetic Engineering in Plants

How are GM crops generated in the first place? Transgenic plants are the result of application of recombinant DNA technology, which combines DNA from two different species, and often involves manipulation of genes in bacteria (Becker, 2009). The common method in plants involves inserting a gene into the plasmid, or circular DNA piece, of a bacteria called Agrobacterium tumefaciens. The bacteria easily infects plant cells and the desired foreign gene, or transgene, such as one enhancing crop yield or providing insect resistance, gets incorporated into the genome of the plant cells. The cells replicate and generate a plant with a new, special trait.

Becker, 2009.

Environmental Risks

The major risk associated with GM plants is that they will escape and disrupt natural ecosystems as invasive species (Wolfenbarger and Phifer, 2000). The process starts with gene flow, the exchange of alleles, or alternate forms of a gene, between two populations. This can occur either by the transfer of individual plants or by the transfer of gametes in the form of pollen which produces hybrid plants in the wild.

According to a recent review in Nature, gene flow will not necessarily lead to introgression, “the permanent incorporation of genes from one set of differentiated populations (species, subspecies, races and so on) into another” (Stewart et al, 2003).  The scientists recommended looking at risk on a case-by-case basis depending on the transgene, the crop species, and the genetic relationships between the crop and local native species. Some genes such as ones improving fiber quality have neutral effects, while others, such as a gene that produces the herbicide Bt toxin, will give hybrid plants an evolutionary advantage.

Wolfenbarger and Phifer. 2000

Technologies that Limit Gene Flow

Recently, plant scientists have been investigating the possibility of using GURTs, or gene use restriction technologies, which manipulate genetics to reduce the spread of potentially harmful transgenes (Hills et al., 2007). One of the more controversial GURTs is terminator technology, which produces sterile seeds, the idea being that this would stop the spread of transgenes by seed transmission into the environment. Critics argue that this technology will hurt small-scale farmers who traditionally save seeds for the next generation (Monsanto.com). The terminator is a three-step system that makes use of promoter regions, which are regulatory pieces of DNA that control whether a gene is expressed. The last step introduces a sterility gene in a tissue-specific fashion.

Hills et al. 2007

Conclusions and Personal Opinions

Genetic engineering has many potential benefits such as alleviating malnutrition and hunger in the developing world, so I do not think that it should be banned. However, the technology may be harmful to the environment and to farmers under certain circumstances. I think that we need careful regulation driven by science-based risk assessment. The technology alone is not evil, but we have to fully take into account the implications of its use. Scientists should combine their skills with those of politicians and activists towards the ultimate goal of reaping the most benefits with the least harm.

References

Becker, Wayne, Kleinsmith Lewis, Hardin Jeff, and Bertoni Gregory. The World of the Cell. San Francisco: Pearson, 2009. Print.

Hills, M., Halls, L., Arnison, P., and A. Good. "Genetic use restriction technologies (GURTs): strategies to impede transgene movement." Trends in Plant Science. April 2007. 12(4): 177-183.

Shapiro, Robert. "Is Monsanto going to develop or sell terminator seeds." www.monsanto.com

Stewart, C.N., Halfhill, M.D., and S.I. Warwick. "Transgene introgression from genetically modified crops to their wild relatives." Nature reviews: Genetics. October 2003. 4: 806-817.

Wolfenbarger, L.L. and P.R. Phifer. "The Ecological Risks and Benefits of Genetically Engineered Plants." Science. 15 December 2000. 290: 2088.