Transgenic plants and genetically modified organisms are both created by selecting a specific gene or genes from one species and placing it into the DNA of another species.This results in a phenotypic change in the species that the gene(s) was implanted into. There are two methods for introducing a foreign gene into an organism. The first method is using a bacterium as a vector, and the second is using a gene gun, which is sometimes referred to as biolistics.

Key ScientistsIn 1981, Eugene Nester and Mary Dell

Chilton came up with a way in which

foreign genes could be introduced into

plant cells creating transgenic plants.

They used the Ti plasmid (tumor

inducing plasmid) that is carried by soil

bacteria called Agrobacterium

tumefaciens.

Eugene Nester

Mary Dell Chilton

How does a vector create transgenic plants?

1. A foreign gene is inserted into the T region of a plasmid in a bacterium.

2. The bacterium gains access to a plant through a wound such as a torn leaf or broken branch.

3. The vector enters the nucleus of a plant cell.

4. The T region becomes incorporated into a chromosome in the plant cell.

5. The foreign gene is now part of the plant’s DNA, changing the plant’s phenotype.

Agrobacterium tumefaciens cells attached to a plant cell.

This bacteria can only inflict organisms such as beans, peas and potatoes.

The Agrobacterium tumefacien bacteria is a vector, which means it enables the transportation of foreign genes into plants. This bacteria contains a tumor inducing (Ti) plasmid. The T region of the plasmid becomes incorporated in the plant cell.

1. Tungsten or gold particles are coated with DNA.

2. The particles are accelerated in a partial vacuum.

3. The target tissue is placed in the path of the accelerating particle.

4. The metal atom passes right through the cell, but the DNA is left inside the cell, becoming a part of the organism’s original DNA.

5. A marker gene is used so scientists can be sure that the gene entered the cell, and stayed inside.

6. The new genetically modified cell grows and replicates

How does a gene gun work?

Gene guns are used to place foreign genes into wheat, corn and rice.

Gene gun

Benefits of Transgenic Plants

Enhance, taste, quality, and nutrition Improved resistance to disease, pests, and herbicides Reduce maturation time (grow faster) Increase shelf life Weather tolerance (temperature, drought, etc.) Pharmaceuticals: researchers are working on developing

edible vaccines in tomatoes and potatoes Decrease Pollution: Some genetically modified plants and

poplar trees were designed to clean up heavy metal pollution from contaminated soil

Drawbacks of Transgenic Plants

The process of engineering genetically modified plants takes a very long time and is expensive

Possibility of causing new allergic reactions Long term effects on human health are unknown Genes could transfer to untargeted species such as weeds,

making them resistant to herbicides and pests Negative impact on ecosystems: the pollen from transgenic

corn killed many monarch caterpillars because the pollen was carried by the wind onto milkweed, which is their food source.

Golden Rice

Golden rice was genetically modified to have high levels of beta carotene, which is used by the body to synthesize vitamin A. The rice contains genes from a daffodil, pea, bacterium and a virus. Many people don’t get enough vitamin A from their diet and if they have a severe enough deficiency they can go blind.

White Rice and Golden Rice

Transgenic Corn

Transgenic corn was created to be pest resistant, specifically to the corn borer “Ostrinia nubilalis”. This corn would increase the farmer’s corn yield, and save them money because they wouldn’t have to throw away corn that was destroyed by pests.

Transgenic corn is on the left of each picture and regular corn is on the right.

Left: Ostrinia nubilalis

The Favr Savr Tomato

One of the first approved modifications to an organism was a tomato, in which the gene that causes the tomato to ripen was minimized in order to give the tomato a longer shelf life.

The Endless Summer Tomato

Scientists found, copied, and rebuilt a gene that lets tomatoes stay on the vine longer without softening and spoiling. This means that they can develop more sugars and acids, which gives them more flavour.

Genetically Engineered Insulin producing Bacteria

Insulin is needed in humans to control the level of sugars in the blood.

The gene for insulin production in humans has been isolated and inserted into bacterial cells. Theses cells then transcribe and translate the gene into the protein insulin. The bacteria then replicate, creating even more bacteria to produce insulin.

This was a significant discovery because previously people with diabetes relied on insulin from other animals, such as pigs. However, some people were allergic to the insulin produced by pigs.

Alba the fluorescent bunny

An Aequorea victoria jellyfish

Alba: The Fluorescent Rabbit

Though mainly used for genetically modifying plants there have been cases where this technology has been used to modify animals as well. An example of this is the infamous rabbit Alba, in which a gene from a jellyfish was inserted into the DNA of a rabbit so it would glow green when exposed to ultra violet light. Alba was created solely for the purpose of art.

Spider Goats

Spider silk is the strongest natural fiber known to science. It is tougher than Kevlar, stretches better than nylon, and is five times stronger than steel (weight for weight).A spider gene was incorporated into the DNA of a goat embryo. The gene codes for the synthesis of a protein found in spider webs. The gene causes the goat to produce this web protein in its mammary glands, and it comes out in its milk. Scientists then take the protein and form it into thin strands. The farm that this is occurring at is located outside of Montreal, Canada. Scientists have only managed to make strands of web about 1/10 as strong as a spider can make, but are working on making them stronger. The spider silk could potentially be used for sutures, artificial ligaments and tendons, or bullet proof vests.

Other examples of genetically modified animals…

Salmon have been bio-engineered to grow twice as fast as they would normally. Salmon usually only produce a growth hormone at certain times of the year. The engineers were able to keep the hormone active by using another gene from an eel-like fish called an ocean pout that acts like an on switch for the hormone. The switch is kept on all the time, so the salmon grows much faster.

Dairy cows are being bio-engineered to have a 10% increase in milk production.

Cattle are being genetically modified so that they are resistant to mad cow disease (currently being developed).

Facts:

The majority of transgenic crops grown are herbicide and insect resistant soybeans, corn, cotton, canola, and alfalfa.

The United States grows 53% of the transgenic crops in the world, while Canada only grows 6%.

Since 1994 only about 40 genetically modified foods have been approved in Canada

Labeling genetically modified plants isn’t mandatory. However, some companies choose to label their products anyways.

Conclusion

Although genetically modified foods have benefits, there are still risks, and we must be cautious.

Genetically modified organisms still remain a controversial issue, and will probably continue to be debated for a long time to come.

We must take into account the health, environmental, and economic effects that these organisms can result in.

Who knows, maybe in the future we will be creating genetically modified humans!!!

QUIZ1.True or false? The gene gun technique of

introducing foreign genes into an organism is also known as biolistics.

Answer: TRUE

2. In 1981, who developed the Ti plasmid method of introducing a foreign gene into plants?

A. Clinton Marsh and Evelyn Nelson

B. Mary Chilton and Eugene Nester

C. James Watson and Francis Crick

D. Edward Smith and Margaret Clarke

Answer: B

3. True or False? Golden rice was bio-engineered to contain high amounts of vitamin A.

Answer: FALSE It was bio-engineered to have high amounts of ß-catotene, which is made into vitatim A molecules by your body.

4. Which of the following is not a benefit of genetically modified organisms?

A. Prolonged shelf life of vegetables.

B. Higher tolerance of weather.

C. Interactions with other plants or wildlife.

D. Resistance to disease, pests, and herbicides.

Answer: C

Works Cited“Bioengineered Tomatoes Taste Great.” The CBS Interactive Business Network. 2010. Online. 28 Nov. 2010.

<http://findarticles.com/p/articles/mi_m3741/is_n7_v43/ai_17294707/>

Di Giuseppe, Maurice, et al. Biology 12. Toronto: Nelson, 2003. Print.

“Genetically Modified Foods and Organisms .” Human Genome Project Information. 2008. Online. 27 Nov.

2010.

<http://www.ornl.gov/sci/techresources/Human_Genome/elsi/gmfood.shtml>

“Genetically Modified Salmon Hearings Begin.” CBC News. 2010. Online. 30 Nov. 2010.

<http://www.cbc.ca/canada/prince-edward-island/story/2010/09/20/con-gm-salmon-hearing.html>

“Mixing Spiders with Goats to make bullet proof vests.” You Tube. 2010. Online Video clip. 1 Dec. 2010.

<http://www.youtube.com/watch?v=q0WCjX8jUE4>