GENETIC MODIFICATION OF PLANTS
New traits introduced to crop plants by genetic engineering have the potential to increase crop yields, improve agricultural practices, or add nutritional quality to products. For example, transgenic crop plants capable of degrading weed killers allow farmers to spray weeds without affecting yield. Use of herbicide-tolerant crops may also allow farmers to move away from pre-emergent herbicides and reduce tillage, thereby decreasing soil erosion and water loss. Transgenic plants that express insecticidal toxins resist attacks from insects. Crops engineered to resist insects are an alternative to sprays, which may not reach all parts of the plant. They are also cost effective, reducing the use of synthetic insecticides. Genetic engineering has also been used to increase the nutritional value of food; “golden rice” is engineered to produce beta-carotene, for example. Edible vaccines, present in the plants we eat, may be on the horizon.
The new traits expressed in such transgenic plants are derived from a variety of other organisms. Scientists have given a gene from the bacterium Salmonella to cultivars of soybeans, corn, canola, and cotton to degrade the pesticide glyphosphate (Roundup TM). The gene for the insecticidal toxin in transgenic cotton, potato, and corn plants comes from the bacterium Bacillus thuringiensis (Bt). One of the genes allowing vitamin A production in golden rice is derived from the bacterium Erwinia uredovora; others are from the daffodi
HOW IS IT DONE?
The characteristics of all living organisms are determined by their genetic makeup and its interaction with the environment. The genetic makeup of an organism is its genome, which in all plants and animals is made of DNA. The genome contains genes, regions of DNA that usually carry the instructions for making proteins. It is these proteins that give the plant its characteristics. For example, the colour of flowers is determined by genes that carry the instructions for making proteins involved in producing the pigments that color petals.
Genetic modification of plants involves adding a specific stretch of DNA into the plant’s genome, giving it new or different characteristics. This could include changing the way the plant grows, or making it resistant to a particular disease. The new DNA becomes part of the GM plant’s genome which the seeds produced by these plants will contain.
The first stage in making a GM plant requires transfer of DNA into a plant cell. One of the methods used to transfer DNA is to coat the surface of small metal particles with the relevant DNA fragment, and bombard the particles into the plant cells. Another method is to use a bacterium or virus. There are many viruses and bacteria that transfer their DNA into a host cell as a normal part of their life cycle. For GM plants, the bacterium most frequently used is called Agrobacterium tumefaciens. The gene of interest is transferred into the bacterium and the bacterial cells then transfer the new DNA to the genome of the plant cells. The plant cells that have successfully taken up the DNA are then grown to create a new plant. This is possible because individual plant cells have an impressive capacity to generate entire plants. On rare occasions, the process of DNA transfer can happen without deliberate human intervention. For example the sweet potato contains DNA sequences that were transferred thousands of years ago, from Agrobacterium bacteria into the sweet potato genome.
There are other ways to change the genomes of crops, some of which are long established, such as mutational breeding, and others of which are new, such as genome editing, but in this Q&A we are focusing on GM as it is currently usually defined for regulatory purposes in Europe.
DISADVANTAGES AND ADVANTAGES OF GENETICALLY CROPS
Nearly 90 percent of all the crops grown in the United States have been touched by science. Genetically modified organisms, or GMOs, are plants that have had their genes manipulated. They give the crops new characteristics, like insect resistance, larger yields, and faster growing traits. The use of GMOs is hardly new, but many believe that sufficient research on the long term effects has not been conducted. In order to understand more about genetically modified crops let’s take a look at the pros and cons.
THE ADVANTAGES OF GENETICALLY MODIFIED CROPS
- Better For The Environment
Since GMOs require much less chemicals to thrive, the impact on the environment is lessened. The pesticides and other chemicals commonly used on non GMO crops emit greenhouse gases and pollute the ground soil.
- Resistance To Disease
One of the modifications made to the crops is an added resistance to disease that would normally kill off the crops. This keeps the yields high and the prices for the consumers low.
GMOs provide a stable and efficient way to sustain enough crops to feed the ever growing population of people in the world. This was the main goal of GMO crops in the first place.
- Increased Flavor and Nutrition
Along with resistances to insects and disease, the genes of the crops can also be altered to have a better flavor and increased nutritional value. This is good all around.
- Longer Shelf Life
Genetically modified foods have a longer shelf life. This improves how long they last and stay fresh during transportation and storage.
- Keeps It Affordable
One of the biggest effects that the use of GMOs has had on our every day life is the prices of produce and other foods. Since more crops can be yielded, the prices can be much lower.
THE DISADVANTAGES OF GENETICALLY MODIFIED CROPS
- Cross Contamination
The pollen from the genetically modified plants is also contaminated. When this pollen is around other plants, even things like grass or weeds, they cross pollinate. This could develop “superweeds” that have the same resistance properties as the crops.
- Allergies On The Rise
Ever since the introduction of GMO foods, the amount of childhood food allergies has risen significantly. The exact link to GMO has not yet been found, but many believe this is due to insufficient research in the area.
- Less Effective Antibiotics
The crops that have been genetically modified have antibiotic properties put into them in order to make them immune to certain diseases. When you eat these foods these properties are left in your body and can make many antibiotics less effective.
- Not Enough Testing
There has been very little testing and research done on genetically modified foods and the long term effects have not been discovered yet. This makes many people feel uneasy at the high use of these foods.