Transgenic Plants

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Transgenic Plants Genetically Modified
Organisms
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• 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.

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Key Scientists

• In 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
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How does a vector create transgenic plants?
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. 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 plants DNA,
   changing the plants phenotype.

Agrobacterium tumefaciens cells attached to a
plant cell.
This bacteria can only inflict organisms such as
beans, peas and potatoes.
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How does a gene gun work?

• Tungsten or gold particles are coated with DNA.
• The particles are accelerated in a partial
  vacuum.
• The target tissue is placed in the path of the
  accelerating particle.
• The metal atom passes right through the cell, but
  the DNA is left inside the cell, becoming a part
  of the organisms original DNA.
• A marker gene is used so scientists can be sure
  that the gene entered the cell, and stayed
  inside.
• The new genetically modified cell grows and
  replicates

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

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• 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.

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• 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 dont get enough
• vitamin A from their diet and if they
• have a severe enough deficiency
• they can go blind.

White Rice and Golden Rice
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Transgenic Corn Transgenic corn was created to
be pest resistant, specifically to the corn borer
Ostrinia nubilalis. This corn would increase
the farmers corn yield, and save them money
because they wouldnt 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
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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.
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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.

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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.
An Aequorea victoria jellyfish
Alba the fluorescent bunny
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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.
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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).

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• 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 isnt
  mandatory. However, some companies choose to
  label their products anyways.

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• 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!!!

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QUIZ

1. True or false? The gene gun technique of
   introducing foreign genes into an organism is
   also known as biolistics.

Answer TRUE
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• 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
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• 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.
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• 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
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Works Cited

• Bioengineered Tomatoes Taste Great. The CBS
  Interactive Business Network. 2010. Online. 28
  Nov. 2010. lthttp//findarticles.com/p/articles/mi_
  m3741/is_n7_v43/ai_17294707/gt
• 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.
• lthttp//www.ornl.gov/sci/techresources/Human_Geno
  me/elsi/gmfood.shtmlgt
• Genetically Modified Salmon Hearings Begin.
  CBC News. 2010. Online. 30 Nov. 2010.
  lthttp//www.cbc.ca/canada/prince-edward-island/sto
  ry/2010/09/20/con-gm-salmon-hearing.htmlgt
• Mixing Spiders with Goats to make bullet proof
  vests. You Tube. 2010. Online Video clip. 1 Dec.
  2010. lthttp//www.youtube.com/watch?vq0WCjX8jUE4gt