Genetically Modified Organisms (GMOs), usually plants or bacteria, have been genetically engineered to increase efficiency or to fit a certain purpose. Scientists can take a desirable gene from the same species- or even from a completely different species- and transfer it to another organism, which will then express the gene as if it was its own. Plants, including the food we eat, are often genetically modified to improve yield by giving them characteristics such as disease or frost resistance, or to increase size or improve taste. Bacteria can be engineered to create human proteins such as insulin, or even to clean up oil spills.
This cutting-edge science, like all new discoveries, has garnered plenty of criticism and controversy. Besides the ethical concerns of playing God, people are worried that tinkering with the genetic harmony of the world could have disastrous effects that we are unable to predict. Although scientists have proved that GM crops are much safer than crops sprayed with pesticides, skeptics worry that GM crops could create multi-resistance superbugs or, through cross-pollination, superweeds.
With a growing population and static supply of land, GM proponents believe this technology is absolutely necessary to make sure we can produce enough food for the world. By creating plants that can persevere in harsh conditions, the amount of land available for crops is vastly increased. Therefore, the benefits outweigh the potential setbacks.
For this lab, we will be testing whether or not certain plants have been genetically modified. Because GM products in the U.S. do not need to be labeled, this is an important technique. The easiest and most effective way to determine whether or not a food has been genetically altered is through a process called Polymerase Chain Reaction (PCR). PCR is a way to, through replication, amplify a small amount of DNA very rapidly. The process has many applications, including crime scene analysis, where DNA samples are often too tiny to test, and in the identification of fossils containing very little intact DNA.
First, we will need to extract the DNA from our food source. To do this, we must break down the cell wall by grinding the material with a mortar and pestle, and then break open the cell membrane and nuclear membrane by putting the sample in an extremely hot water bath. DNA is supposed to stay in the nucleus, however, and an enzyme called DNAse (kills foreign DNA), will destroy our sample. To prevent this, we will use Instagene Matrix Beads, which kill enzymes, keeping our DNA safe from DNAse.
The second day we will use PCR to mass produce our DNA sample for testing. The ingredients necessary for PCR are DNA polymerase, lab-created RNA primer, which targets specific genes, nucleotides, and the DNA we want to amplify. Almost all GM plants contain a Ti (tumor-inducing) plasmid. Because plants do not have vital organs, a tumor is not devastating to its health. Ti plasmids are used because they are the easiest way to transfer genetic material from a bacterium to a plant cell. We will have two separate primers for our PCR: one to test the GM DNA and another to test a control plant's DNA. This control is necessary to make sure the lab actually worked. If our results for the GM food turn out negative, it may simply be because our experiment failed. The control prevents this potentially incorrect conclusion.
Finally, on the third day, we will use Gel Electrophoresis to test our DNA samples. Compared to the marker and our plant control, we will be able to determine whether or not our sample food has been genetically modified.
