Two weeks ago I gave a (group) presentation in my biology class on a 1999 paper by Arpad Pusztai on GMOs (Genetically Modified Organisms). Pusztai was leading a group of scientists at the Rowett Institute in Scotland which was developing a test paradigm that would assure the validity and safety of GMO crops, but to their surprise, they discovered serious health effects that could only have been caused by the insertion of the transgene (not the transgene itself, but the process of insertion). Pusztai was appalled to learn that GMO products were already on the market, and when he publicized his findings, the public outrage was so great that major food chains resorted to removing GMO ingredients from their products in Europe, and legislation was introduced throughout Europe for the labeling of GMO products. Of course the biotech industry fought back, discrediting Pusztai, and he was suspended from the Rowett Institute (which does a lot of research funded by the biotech industry). Later, his paper about the research was formally published (under threat) in ‘The Lancet’, which had the paper reviewed by six peers instead of the usual two because of the intensity of the controversy. Five of the reviewers approved publication; one dissented. During this time, although hundreds of articles were published in Europe about the controversy, only two articles were published here in the States. For some reason the media weren’t as interested here.
For my presentation I wanted to learn about the process of genetically modifying plants, so I dug in. I had heard about the gene-gun, which blasts genes into the nucleus like a B-B gun, where they usually obliterate the cell altogether. In a few cases (1 in 10,000) the cell survives and the new gene lands in the DNA at some random location. Although they used to use that method more in the past (and still do in some cases), it turns out that in about 90% of the cases now, they use a bacterium (Agrobacterium tumefaciens) to do the dirty work, instead. This is a pathogenic soil bacterium that causes tumors in many species of plants. The tumor-inducing genes in the bacterium are deleted, and the desired gene sequence is cloned in the T-DNA of the bacterium. (That, by the way, is the "precise" part of the process that biotech scientists point to in their defense of GMOs. They don’t bother to share the rest of the story.) The plant seedlings are heated to place them under stress, making them susceptible to the bacteria. The bacteria attach to the cell, and using virulent genes in a biological process known as T4SS (Type IV secretion system), they poke the new gene into the plant cell along with a promoter to turn on transcription. This promoter, known as the Cauliflower Mosaic Virus (CaMV), is one of the most powerful promoters known. Depending on where it lands in the plant’s DNA, it can promote not only the transcription of the new transgene, but other genes downstream or even on other chromosomes. This carries huge unintended risks and is the detail in the GMO process that has scientists very concerned. Although Pusztai’s tests did not identify this as THE element that resulted in the deleterious health effects in the rats he was testing, he suspects that it is likely involved.
As if this weren’t enough, once the transgene is in the plant, the A. tumefaciens bacteria are no longer needed, so the plant cells are treated with antibiotics to kill off the agrobacteria before being propagated to crops. It is about 50% effective; some bacteria survive and are propagated to the crops along with the new cells. Unfortunately, this is yet another routine use of antibiotics, contributing to the serious problem we have of increasing bacterial resistance to antibiotics.
The bottom line is that there are huge risks with GMOs. Their safety has not been established, and the few independent tests we do have indicate potential for serious health problems. As these problems are not acute (i.e. immediate and severe), but rather chronic (developed over time), it is very difficult to make the association. Researchers are reluctant to take on the biotech giants, so the tests we so desperately need to understand this technology don’t happen.
Here is a 2009 quote from Pusztai, ten years after his controversial paper was published: "One gene expressing one protein is the basis of genetic engineering, but the Human Genome Project discovered [only] 23,000 genes, and there are 200,000 proteins in every cell. With this discovery, genetic engineering should have disappeared into the dustbin."
I feel like I’m only scratching the surface in understanding the depth of this problem, but I thought I would share what I learned in preparing for my presentation. This is nasty business.
My sources:
• Viral DNA dangers. (2009, June). Retrieved March 10, 2013, from GM-free Scotland: http://gmfreescotland.blogspot.com/2011/02/viral-dna-dangers.html
• Agrobacterium. (2010, December). Retrieved March 10, 2013, from GM-free Scotland: http://gmfreescotland.blogspot.com/2011/04/agrobacterium.html
• Agrobacterium tumefaciens. (2013, March 10). Retrieved from Wikipedia, the free encyclopedia: http://en.wikipedia.org/wiki/Agrobacterium_tumefaciens
• Gene gun. (2013, March 10). Retrieved from Wikipedia, the free encyclopedia: http://en.wikipedia.org/wiki/Gene_gun
• Boyle, R. (2011, January 24). How To Genetically Modify a Seed, Step By Step. Popular Science. Retrieved March 10, 2013, from http://www.popsci.com/science/article/2011-01/life-cycle-genetically-modified-seed
• Ewen, S. W., & Pusztai, A. (1999, October 16). Effect of diets containing genetically modified potatoes expressing Galanthus nivalis lectin on rat small intestine. The Lancet, 354, 1353-1354. Retrieved March 10, 2013, from http://www.sciencedirect.com.proxy.cc.uic.edu/science/article/pii/S0140673698058607
• Pitzschke, A., & Hirt, H. (2010, February 11). New insights into an old story: Agrobacterium-induced tumour formation in plants by plant transformation. The Embo Journal, 29, 1021-1032. doi:10.1038/emboj.2010.8
• Pusztai, A. F. (1998). SOAEFD flexible Fund Project RO 818. Report of Project Coordinator on data produced at the Rowett Research Institute (RRI), Rowett Research Institute. Retrieved March 14, 2013, from http://www.rowett.ac.uk/gmo/ajp.htm
• Roseboro, K. (2009, June). Arpad Pusztai and the Risks of Genetic Engineering. Organic Consumers Association. Retrieved March 13, 2013, from http://www.organicconsumers.org/articles/article_18101.cfm
• Smith, J. M. (2003). Seeds of Deception. Yes! Books.
