Table of Contents
Introduction
Genetically modified foods may be defined as products which has its genomic DNA specifically altered to achieve a certain function. Genetically modified foods are often in the news in one reason or the other. Whatever position one takes in the GMO debate, it is very important to test foods found in the grocery store for the presence of GMO-derived products. DNA isolation were performed on food products (processed corn and oatmeal), and the DNA amplified by polymerase chain reaction(PCR) on the food samples to amplify the DNA sequence of genetic organisms in the food samples. The amplicons, together with molecular weight marker, are analyzed using agarose gel electrophoresis.
Results
After the gel electrophoresis, a photograph of the gel was taken and analyzed by looking at the test food lanes to determine if the DNA fragments for the test food with GMO primer and test food with plant primer are present or not on the gel.
The test sample, processed corn, tested positive for both plant and GMO DNA primers. This can be seen in lanes 3&4 and 5&6. The fragments which appeared were around 203bps and 455bps in lengths. Also, primer dimers occurred in lanes 4&6 at the bottom.
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DNA is negatively charged, and it was repelled by the negative electrode and attracted by the positive electrode when current of 100volts was applied across the gel during the electrophoresis. The DNA separated because different DNA fragments move through the gel matrix at different rates. Hence, the different bands obtained on the gel.
The processed corn showed a positive test for GMO DNA, indicating that it has GMO DNA insert. This did not come as a surprise because the pack of the processed corn indicated with the inscription “genetically engineered”. However, to verify the exactness, molecular weight marker found in lane 7 along with the positive control were used. The band found for the processed corn aligned with both the GMO positive controls and the molecular weight marker at about 203bps.
As stated in the results, primer dimers were observed at lanes 4&6. These occurred as a result of the two primers anneal with each other during the PCR process and then were elongated by the taq enzyme. When gel electrophoresis was conducted, the two primers were pulled by the positive electrode beyond the molecular weight marker, hence, the faint bands.
A setback encountered is that, the non-GMO negative control band not showing up in lane 1. One possible explanation could be that the negative control oatmeal was not ground up enough, and this could affect the release of the DNA. Therefore, there was little or no DNA in the in the instaGene. Another reason could also be that too much oatmeal sample was in the instaGene causing it to ‘over work’ which could not destroy the DNase. This may have destroyed the DNA, leaving nothing for the PCR to amplify and gel electrophoresis to separate Conclusion Even though minor difficulties were observed, the GMO detection analysis conducted confirmed the presence of GMO in the processed corn purchased from the Target grocery store in Chicago. Gel electrophoresis of the PCR amplicons of the test sample (processed corn) to determine the size of the GMO DNA sequence present. Molecular weight marker at lane 7, negative template controls at lanes 1&2 and 8&9, GMO positive control with PMM and GMM at 5&6 respectively, and test sample with PMM and GMM at 3&4 respectively.
References
- ALTSCHUL, Stephen F.; GISH, Warren; MILLER, Webb; MYERS, Eugene W. and LIPMAN, David J. Basic local alignment search tool. Journal of Molecular Biology, October 1990, vol. 215, no. 3, p. 403-410
- ANKLAM, Elke; GADANI, Ferrucio; HEINZE, Petra; PIJNENBURG, Hans and VAN DEN EEDE, Guy. Analytical methods for detection and determination of genetically modified organisms in agricultural crops and plant-derived food products. European Food Research and Technology, January 2002, vol. 214, no 1, p. 3-26.
- BORLAUG, Norman E. Ending world hunger. The promise of biotechnology and the threat of anti-science zealotry. Plant Physiology, October 2000, vol. 124, no. 2, p. 487- 490.
- BRUDERER, S and LEITNER, K. Genetically Modified Crops: molecular and regulatory details. Agency BATS. July 2003. Portable Document Format. Available from Internet: http://www.bats.ch/gmo-watch/GVO-report140703.pdf.
- COLLONNIER, Cecile; SCHATTNER, Alexandra; BERTHIER, Georges; BOYER, Francine; COUE- PHILIPPE, Geraldine; DIOLEZ, Annick; DUPLAN, Marie N.; FERNANDEZ, Sophie; KEBDANI, Naima; KOBILINSKY, Andre; ROMANIUK, Marcel; De BEUCKELEER, Marc; De LOOSE, Marc; WINDELS, Pieter and BERTHEAU, Yves. Characterization and event specific-detection by quantitative real-time PCR of T25 maize insert. Journal AOAC International, March 2005, vol. 88, no. 2, p. 536-546.
- COTE, Marie J.; MELDRUM, Allison J.; RAYMOND, Phillippe and DOLLARD, Cheryl. Identification of genetically modified potato (Solanum tuberosum) cultivars using event specific polymerase chain reaction.
- Molecular Biology Laboratory Manual on detection of genetic modified in food samples, provided by Dr. C. Watson, Roosevelt University, Chicago, Illinois.
