Wednesday, 28 March 2012

Genetic Engineering of Foods and the Fight Against Malnutrition: Golden Rice


 Jonathan O’Sullivan - 42899268

Traditional breeding has been extremely useful in selecting certain desired traits in crops. It has had a major influence on modern sources of foodstuffs through selective breeding to accentuate pre-existing characteristics. However, Genetic  Engineering is a more precise and sophisticated method in crop development than traditional practices, as specific traits are targeted at the genotypical level rather than via its phenotype. These Genetically Modified (GM) foods are made by interchanging the gene sequences between different species resulting in various benefits, including increased nutritional value, as in Golden Rice (Kartha, 2010; Villano, 2000). The GM food, Golden Rice, is biofortified with β-carotene, a precursor of Vitamin A, which will allow developing countries to combat malnutrition and Vitamin A deficiency (Mayer, 2005; Potrykus, 2011) (See Figure 1).

Figure 1: Example of fully grown Golden Rice in a field


(Graham, 2010)

Representatives from the WHO acknowledge that annually 250,000-500,000 children in developing countries  become visually impaired due to dietary vitamin A deficiency and many will die within the first 12 months of the onset of blindness (Reece, et al, 2012; Potrykus, 2011; Mayer, 2005). Insufficient vitamin A can also greatly impair the body’s immune system, increasing vulnerability to infection, thus accelerating the mortality rate (Graham, 2010; Potrykus, 2011). The genetically modified Golden Rice offers people in these countries, where rice is the staple diet, a lifesaving commodity (Reece, et al, 2012; Mayer, 2005)(See Figure 2).
Figure 2: A child who has become visually impaired due to vitamin A deficiency
 (Mayer, 2005)
The first strain of biofortified Golden Rice, SGR1, was developed in 1999. In SGR1, the gene sequence for the enzyme, Phytoene synthase (PSY), found in the daffodil, Narcissus pseudonarcissus, and the gene sequence for the enzyme, carotene desaturase, crt1, obtained from the soil bacterium, Erwinia uredovora, were inserted into the genome of the rice (Reece, et al, 2012; Graham, 2010; Allen, et al, 2010). These two critical sections of genetic code allow the synthesis of  β-carotene (a precursor to vitamin A), which is stored in the edible endosperm (1.6μg/g of carotenoids) (Reece, et al, 2012; Allen, et al, 2010). It is the β-carotene in the grain that causes the golden colour (Graham, 2010; Rao, 2008). In 2005, a second iteration of Golden Rice, SGR2, was developed using the gene for Phytoene synthase obtained from maize, and the same crt1 gene from the bacterium, which produces 23 times more β-carotene (37 μg/g)( Reece, et al, 2012; Graham, 2010; Allen, et al, 2010). Further research is being conducted to refine the final product more extensively (Potrykus & Ammann, 2010) (See Figure 3).
Figure 3: Flow chart of the chemical pathways involved in producing β-carotene in Golden Rice
 (Mayer, 2005)

Golden Rice can help to reduce chronic health issues involved with vitamin A deficiency in developing countries. However, regulatory government bodies have thus far prevented the widespread use of Golden Rice, largely due to the possible risks of harmful effects on humans, such as causing cancer or severe allergic reactions (Allen, et al, 2010; Kartha, 2010; Villano, 2000; Potrykus & Ammann, 2010). Numerous philanthropic groups, including the Bill & Melinda Gates Foundation and Helen Keller International, have donated millions of dollars to organizations that are extensively testing and eventually marketing Golden Rice (IRRI, 2011; Nayar, 2011).  Field trials of SGR2 rice in certain countries, including India, Philippines, Taiwan and the United States, have been conducted in the last few years with encouraging results (Schultz, 2009; Nayar, 2011; Graham, 2010). Eventually, Golden Rice will be bred in locally adapted varieties in all target countries once the necessary safety testing has been completed. Estimated times for the regulated use of Golden Rice in developing countries include 2012 to 2015 (Nayar, 2011; Potrykus & Ammann, 2010)(See Figure 4).

Figure 4: List of Regulatory hurdles for Golden Rice’s Approval

 (Potrykus & Ammann, 2010)

Although GM foods such as Golden Rice offer real benefits in the long term, the amount of time, money and effort that has been poured into these transgenic foods is extensive. The timeline for the progression of GR from developmental stages in 1999 to human consumption is still continuing (See Figure 4). The use of traditional breeding of crops is perhaps a more cost-effective and time-efficient method of the development of improved, refined strains.



Reference List


1.        Allen, R et al. 2010, Year 12 Biology: Student Workbook, BIOZONE International Ltd, Burleigh, pp. 223-225, 239.

2.        Graham, R  2010, ‘Golden Rice:Frequently asked questions’ , Golden Rice Humanitarian Board, viewed 10 March 2012, .

3.        IRRI  2011, 'New Golden Rice partners join forces against vitamin A deficiency', IRRI: International Rice Research Institute, International Rice Research Institute, viewed 10 March 2012, .

4.        Kartha , D  2010, 'Genetically Modified Foods Pros and Cons', Buzzle.com, Buzzle, viewed 11 March 2012, .

5.        Mayer, JE  2005, 'Development and Impact of Golden Rice', Golden Rice, Golden Rice Humanitarian Board, viewed 10 March 2012, .

6.        Nayar, A  2011, Nature: International Weekly Journal of Science, 14 April, Nature Publishing Group, viewed 16 March 2012, .

7.        Potrykus, I  2011, Golden Rice , Golden Rice Humanitarian Board , viewed 10 March 2012, .

8.        Potrykus, I & Ammann, K  2010, 'Regulation must be revolutionized', GoldenRice.org, Macmillan Publishers Limited, viewed 16 March 2012, .

9.        Rao   , CK  2008, 'Golden Rice', FBAE, Foundation for Biotechnology Awareness and Education, viewed 11 March 2012, .

10.     Reece, J et al. 2012, Campbell Biology, 9th edn, Pearson Education, n.p., pp. 836, 898-899.

11.     Schultz, B  2009, 'Golden Rice' Could Help Malnutrition , 3 November, LSU AgCenter, Louisiana, viewed 16 March 2012, .

12.     Sterger , C  2011, Genetically Modified Foods – Pros and Cons, 15 March, WordPress, viewed 16 March 2012, .

13.     Villano, C  2000, Genetically Modified Foods: Safe or Unsafe?, NYU Graduate School of Arts and Sciences, New York, viewed 16 March 2012, .



No comments:

Post a Comment