Biology Issue Report on GM Foods
A Level Biology – Unit 3 Issue Report
Course Code: AN03 Biology A Level 2009
Unit 3 - 6BIO3
Problem – Producing Enough Food for the World’s Growing Population
Food shortages are not a new problem but they have become more widespread in recent years. Food riots took place in Haiti in 2008 following demonstrations over the rising price of food and India suffered drought due to the failure of monsoons in 2009 (1). Famine is a very real issue right now in Africa with the Sahel region of West Africa facing a “worsening food crisis (2)”. In the Horn of Africa (see fig 1) in 2011 tens of thousands of people died (estimates range between 50,000 and 100,000) from famine following a drought said to be the worst in 60 years (3).
Climate change is one of the reasons behind the drought that triggered East Africa’s 2011 famine. As climate change is unlikely to be reversed in the near future, reduced rainfalls are expected to continue and a solution is needed to combat the diminished growth of crops and yield in arid, populated areas. The world population is nearly 7 billion at the moment and the United Nations estimates it will reach 9.3 billion by the middle of the century (4). The majority of the increase is expected to be in developing countries. The UN also states that food production must double by 2050 to meet the demand of the world’s growing population (5). These two sets of figures do not necessarily tally but the current population is not currently receiving enough food and rising population is not the only factor in food demand.
In addition to population growth and reduced rainfall, soil fertility can be depleted by a lack of access to fertiliser and bad farming practices which reduces the area suitable for crops and pasture.
Genetic Modification of Crops – A Biological Solution
One solution in combatting food shortages and ensuring healthy yield is ensuring that crops are chosen for planting which are able to grow with a minimal amount of water. In this way, maximum efficiency is gained from the investment (area, water, time etc) in the crop and it is more likely to withstand times of drought.
Genetic modification of crop plants is one way in which plants can be grown which need less water. This is currently a focus for seed producing companies as an estimated 69-70% of the world’s fresh water is used for irrigation (6 & 7). Drought resistant versions of maize (corn), wheat and sugar cane are currently under development.
Biofuel production is competing with food production for farming land. At the University of Liverpool, biologists are sequencing the genome of the Madagascan Kalanchoe fedtschenkoi plant to find out how it functions at night, when it takes in most of its carbon dioxide requirement. According to the Reseach Intelligence page on the University’s website this makes it “ten times more water-efficient than major food crops like wheat” (8). The biologists hope to use the plants genetic code to make biofuel crops able to grow in harsh environments, leaving fertile farmland for crops.
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Monsanto is a Fortune 500 biotechnology company with a goal to double yields in our core crops by 2030 using advanced plant breeding and biotechnology (9). In December 2011 the United States Department of Agriculture approved Monsanto’s drought-resistant variety of corn, MON 87460, which was developed using Agrobacterium-mediated transformation and has the gene for Bacillus subtilis cold shock protein B (CspB) inserted into its genome. CspB is a protein which helps bacteria adapt to environmental stresses.
“CspB is known to bind and unfold secondary RNA structures that compromise the ability of the cell to translate those RNA molecules, thus helping to preserve normal cellular functions” (11)
Agrobacterium is a genus of bacteria that cause tumours in plants by transferring a tumour-inducing transfer DNA (T-DNA) segment to the host, which then becomes incorporated into the nuclear genome. A. tumefaciens, for example, causes Crown Gall disease in plants (see fig 2).
Agrobacterium-mediated transformation is a process whereby A. tumefaciens is used to transfer transgenic DNA into a host plant’s genome. The resulting plants are generally fertile and can produce further GM descendants.
In my reading on this method I found the following components are needed in the plasmid:
- Border sequences. These sequences of T-DNA mark the ends of the segment of foreign DNA which is to be inserted into the host plant’s genome, and they help guide DNA transfer.
- Virulence genes (vir genes) which help transfer the region of T-DNA but don’t move across themselves.
- Modified region of T-DNA where the disease-causing gene is removed and the new genes are placed
In this way the plasmid that the bacterium would normally use to transfer a harmful gene is used to transfer a desirable gene into a crop plant. The gene is taken into the nucleus and begins to be expressed, producing the desirable phenotype. In the case of the Monsanto corn, this means drought-resistance. Biologists have proven the technique works, as documented in the Monsanto application:
“The presence of the MON 87460 insert in the maize nuclear genome is best shown by the Chi square (χ²) analysis of the segregation data. The results show that inheritance of the drought-tolerance trait in MON 87460 follows Mendelian principles. This indicates that the single insert is stably integrated in the nuclear genome and is neither located in the mitochondria nor in the chloroplasts.”
Chi Squared is a statistical test measuring the differences between expected outcomes and observed outcomes. In this case, the maize would not be expected to contain the transgene. The statistical significance of the Chi Squared test shows that the transgene can be passed on to multiple future generations of the plant.
In addition, Monsanto state they have confirmed the insert is stably integrated within the maize’s nuclear genome and being inherited in Mendelian fashion through the use of Southern Blot analyses. Southern Blot testing detects the specific sequence of DNA in the corn to show the location of the transfer DNA. This process involves separating the DNA strand and then allowing it to form base pairs with a DNA “probe” marked with radioactivity (the technique can also use an enzyme). The radioactive DNA can then be located and shown in what has become widely recognisable as a “genetic fingerprint” as seen in fig 3.
Figure 3 – Example of Southern Blot
The producers of the GM maize tested it against unaltered maize and found that the grain yield for MON 87460 is equivalent to conventional maize in well-watered conditions but under water-limited conditions the yield loss is reduced. The actual data gathered is not available to the public however I have studied the methodology for collecting the data and found that in 2006 Monsanto grew MON 87460 and a conventional control maize at 6 field sites in an area of the United States normally used for maize growing. They also grew the maize in 4 representative field sites in Chile during the 2006-2007 growing season.
“The compositional study compared MON 87460 to the control. Reference hybrids were grown in the same field locations and under the same conditions as the test and control. Where statistical differences occurred, the measured analyte was compared to ILSI ranges for commercial varieties and ranges reported in literature.”
Monsanto Application (11)
These data methods illustrate that the maize will continue to pass on the drought-resistance gene to its progeny. If successfully transferred into the environment and cultivated, these and other genetically modified crop plants could confer an advantage in the harsher growing conditions seen as a result of climate change. Reduced yield loss translates to more food available for consumers. In this way, genetic modification of crop plants contributes towards producing enough food for the world’s growing population.
Key Implications of Using Genetically Modified Crops
Additional undesirable traits can be transferred along with the desirable transgene. One case study, taken from the book “50 Genetics Ideas You Really Need to Know” details a GM soya line which had a Brazil nut gene inserted, along with an inadvertently transferred nut allergen. This mistake was found during the testing process and the soya line was discarded before it went to market but if an undesirable trait makes it into the germ line and the crop spreads this could be injurious to human (or animal/plant) health.
There is also a concern that natural biodiversity could be reduced if certain GM varieties of crops are grown in large quantities, however it is also true that farmers already restrict biodiversity by selecting what kind of crops are grown and where.
People have ethical concerns over “Frankenfoods” and some believe that genetically modifying plants is “playing God”. People don’t necessarily need to follow a religion to feel strongly about tinkering with nature. I have seen several websites opposed to GM foods that list many concerns, such as:
- Reduced nutritional composition
- Chemical usage
- Genetic disorders in consumers
- Mutations in children
Although I have not found any evidence to support the views on the websites I have found, it is perhaps unethical to force people to take genetically modified food without alternative if they genuinely believe it could be doing them and their families harm.
Alternative Approaches to Combatting Food Shortage
Selective plant breeding is an alternative to GM crops that can also help address the food shortage issue. Agricultural scientists select crop plants for their desirable genetic traits such as:
- Shorter stalks and smaller leaves (more energy is devoted to growing the parts that humans eat, less is wasted)
- Better disease or pest resistance
- Better resistance to environmental stresses
These plants are then chosen for planting and the best are taken forward to the next generation. Although this is a more natural method and it raises fewer objections from the public, the GM method is a much faster and surer way to get phenotypic traits into plants.
Another alternative is to use technology such as optical crop sensors, drip irrigation and multi-use, multi-crop machines. Given that many areas with drought problems are also very poor areas then the large financial outlay may be prohibitive.
Evaluation of the Relative Validity of the Information I Gathered and its Sources
A lot of the information used regarding Monsanto GM corn has come from Monsanto’s press releases or the document they prepared for the regulatory bodies. This has the potential to be biased as the firm have financial interest in the corn and are likely to market the best aspects of it, perhaps making it seem better than it is. However, the work they have carried out is regulated by the Food and Drug Administration (FDA) and the documentation I have used is officially scrutinised so I have some faith in the contents. The data on the genes used and the Agrobacteium mediated, Chi Squared and Southern Blot methods of genetic modification and analysis are reflected in both the Monsanto application and the FDA’s Biotechnology Consultation Note BNF 000116
The book “50 Genetics Ideas You Really Need to Know” is written by Mark Henderson, Science Editor for the Times newspaper. He does not have any formal science training that I am aware of, so I reviewed the Brazil nut story on Academics Review website and am satisfied that it is genuine as it appears there also along with a reference to an academic paper on PubMed(12).
Figure 1 – Horn of Africa (red)
Figure 2 – Example of Crown Gall disease
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**** Though demonstrating a good understanding of A level biology this is not a balanced account.