Genetically modified organisms (GMO’s) or genetically engineered organisms (GEO’s) are two of the areas of genetics that are often found full of controversy. They are the organisms that are created by the insertion of a gene from another organism to produce an organism with recombinant DNA.
Inserting genes into a plasmid.
Image by Minestrone Soup.
The creation of GMO’s started with simple bacteria in 1973. Researchers found an enzyme called a restriction enzyme that worked like molecular scissors. They found that they could use restriction enzymes to cut DNA so that genes could be extracted. The ends of the DNA fragments had sticky ends that could be used to reattach it to another strand of DNA. The first thing they did was to extract the gene for the production of insulin and insert it into a plasmid of E. coli. The plasmid gave the bacterium the ability to produce insulin. Considering the only way to extract insulin prior to this was by processing the pancreas of dead animals and cadavers, this was a great advancement in genetic engineering. Insulin could now be produced in a purer form and in large quantities at a much lower cost.
Since that time the insertion of DNA from one organism into the DNA of another to create recombinant DNA has created many new organisms with new or interesting traits.
The production of human proteins by creating a GMO has had some very beneficial outcomes. The production of insulin by bacteria was the first but it has not been the last.
Prior to this technology, the only way to harvest human growth hormone to treat dwarfism or blood clotting factors to treat haemophiliacs was to extract it from other people, cadavers, or animal organs. This could lead to the accidental transmission of blood borne illnesses such as HIV, hepatitis C, and Creutzfeldt-Jakob disease. With the genes for human growth hormone and clotting factors inserted into bacteria, these proteins are now produced without the same risks. Not only are they produced in large quantities, but also the cost of them has decreased dramatically making them more accessible to more people who need them.
The technology has not been limited to bacteria. There are genetically engineered plants and animals as well. One type of pig has been called the “EnviroPig”. Researchers at the University of Guelph have inserted a gene that allows a pig to produce an enzyme that will permit it to metabolize phosphorus. The pig now produces low phosphorus manure that has a much lower impact on the environment.
Pigs always seem to be of interest to researchers. A Scottish company has removed a gene from pigs that prevents their tissues from being rejected if transplanted into humans. Since a pig’s organs perform the same functions and are roughly the same size as a human, their organs could be used for transplants. Advantages to using pig organs are reducing the time waiting for a transplant and decreasing the shortage of transplant organs. The concern is that the transplanted organs may be susceptible to pig diseases that could make their way into the human population.
Did you know?
GloFishThe first pets to contain recombinant DNA were fish. A gene from jellyfish that allow them to glow was inserted into the DNA of zebra fish. They are sold under the trademarkes
Plants used in food production are probably the greatest interest to researchers. In an effort to increase yields and reduce the need for pesticides, the gene from a bacterium was inserted into corn. The bacterium, Bacillus thuringiensis, produces a toxin called Bt toxin that acts as an insecticide. The gene was inserted into corn plants to produce “Bt corn” which has reduced the amount of pesticide needed by corn farmers.
The first GMO plant that was licensed for human consumption was the Flavr Savr tomato. Tomatoes are typically picked while they are still green to maximize shelf life and the flesh is resistant to rough handling. However, picking tomatoes this early left them tasting bland. The Flavr Savr tomato had a gene inserted into it that allowed it to stay on the vine longer to finish the ripening process but the flesh remained firm and resistant to rough handling. This gave the tomato better flavour and a longer shelf life allowing it to be transported easier.
Genetically modified organisms are not without controversy. Some people are concerned that the insertion of genes into organisms that are released into the environment is short sighted. They claim that there have not been enough long-term studies to see how these organisms may affect the natural ecology of where they are introduced.
The most often cited case is for the monarch butterfly. The monarch butterfly only feeds on milkweed plants. The plant is often found growing near or in cornfields. The controversy is that the pollen from Bt corn settles on the leaves of the milkweed plant and the monarch butterfly eats the leaves with the insecticide-laden pollen. The butterfly then dies and or is unable to reproduce. This along with the destruction of the butterfly’s natural habitat has lead to its declining numbers in recent years.
Others fear that the pollen may fertilize natural corn populations and genetically change them forever. Studies have shown that the pollen, which is typically transferred by bees or the wind, has pollinated non-GMO plants as far as 20 km from where the GMO’s are being grown.
Another controversy is associated with a yet to be released technology. The “terminator” gene has been inserted into many seed crops that will not allow their seeds to be used for future plantings. This makes the farmer dependent on the seed company for all seeds for planting since the farmer cannot use seeds from the plants that are harvested. This could have huge implications in the developing world where GMO’s can be created to grow in adverse conditions such as drought or excessive heat. Depending on the cost of these seeds, the farmers from these regions may not be able to afford the seeds from season to season.
One controversy that has had very little news coverage is the patent process for GMO’s. Although life forms cannot be patented in Canada, in countries like the United States it is possible to patent the DNA of a GMO. The ethical and legal implications of this could be quite great. For example, what if it were found that you have a gene that could be used by the wheat plant to make it grow bigger with more grains? What if a company decided to make a GMO using your gene and patented it? The question then becomes, would you still be allowed to use your gene or would you have to pay the company to continue using your gene?
As you can see there are many great things that can be done with genetic engineering but there is still a need to determine the long-term impact that these will have on our planet. Genetic variation is species specific and evolution takes a long time to change the DNA of an organism. These technologies allow the mixing and matching of DNA from different organisms to happen overnight. The technology is still very young and we need to reflect on the benefits and the risks associated with the technology and determine what is reasonable.
- Canadian Food Inspection Agency
- Human Genome Project Information
- Environment Canada
- University of Alberta Resource Guide
Online Research Project
The Internet has become a valuable resource for doing research. Not only can you find articles by scientists and other notable researchers but you can also find news articles that explain stories. In this assignment you are going to explore the Internet in an effort to find out more about THREE genetically modified organisms and the controversy surrounding them.
Part One: Research
- Using the Internet find three or more sources of information about each of your chosen genetically modified organisms.
- Create a table like the one below to present your research.
|Organism Chosen||The benefits associated with GMO’s||The risks associated with GMO’s|
(to society and environment)
|Your opinion about what you learned from your research|