Download Genetically Modified Organisms

Notes:
Write down ONLY the things in
RED!!!
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Genetic Engineering
• Means making changes to DNA in order
to change the way living things work.
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Creates new crops and farm animals.
Makes bacteria that can make medicines.
Can grow human body parts.
Can prevent genetic diseases, change humans.
Altering Organisms isn’t NEW, we’ve been
doing it for 1000’s of years…
It’s called - Selective Breeding.
Selective Breeding
For Example: The Labradoodle
• Look at the following dogs - crossing a Poodle and a
Labrador results in a ‘Labradoodle’
• What features has the Labradoodle inherited from the
Labrador?
• What features has the Labradoodle inherited from the
Poodle?
+
Poodle
+
Labrador
Labradoodle
The simple
addition, deletion,
or manipulation of
a single trait in an
organism to
create a desired
change.
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Major tool is recombinant DNA.
-Recombinant DNA (rDNA) - DNA
joined to other unrelated foreign DNA.
-also called gene splicing.
-tiny segments of a gene are taken out
and replaced.
Transgenic Organisms:
Are organisms that have been altered by
genetic engineering.
• Genetic material changed by other than
random natural breeding.
• Gene transfer - moving a gene from
one organism to another.
Examples of Genetically Modified
organisms:
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Enviropig
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Venomous cabbage
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Web-spinning Goat
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Fast Growing Salmon
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Less Flatulent Cows
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Banana Vaccine
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Cancer Fighting Eggs
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How does it work?
In cross pollination (think Mendel’s peas), we are
combining two traits to get a mixture of results
In genetic engineering, a single gene, a half page recipe in the 52-thousand-page
set of recipe books, can direct the plant to make new traits or remove them
1. The
flounder’s
antifreeze gene
is copied and
inserted into a
small ring of
DNA taken from
a bacteria cell.
2. The DNA ring
containing the
flounder gene is put
into a second
bacterium.
3. This second bacterium is
used to infect the strawberry
cell. The flounder’s antifreeze
gene enters the strawberry’s
DNA.
4. The new GM
strawberry cell is
grown into a GM
strawberry plant
which can be bred
many times.
This diagram shows how one
type of GM food, a strawberry
that resists frost damage is
made. The flounder is a fish that
live in icy seas. It has a gene that
stops it from freezing to death.
Strawberries are soft fruits that
can easily be damaged by frost.
Wonder what
they used to
make this one
blue? – A
different gene
from another
Strawberry cell
organism.
with Antifreeze
gene
Thanks to the new gene, GM strawberries make
a protein which helps them resist frost. They
don’t contain any other fish genes, and do not
taste or smell of fish.
Pros of Genetic Engineering:
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Crops with enhanced characteristics
• Better taste and quality
• Less time to ripen.
• More nutrients, more food, and stress tolerance
• Improved resistance to disease, pests, and herbicides
• New products and growing techniques
Enhanced Animals
• Increased resistance, productivity, hardiness, and feed efficiency
• Better yields of meat, eggs, and milk
• Improved animal health
Environment (helps clean up and keep it clean)
• "Friendly" bioherbicides and bioinsecticides
• Conservation of soil, water, and energy
• Better natural waste management
• More efficient processing
Helps with increased food demands
• More food for growing populations
Cons of Genetic Engineering
Safety
• Potential human health impact: allergens, transfer of antibiotic resistance
markers, unknown effects
• Potential environmental impact: unintended transfer of transgenes through
cross-pollination, loss of flora and fauna biodiversity
Access and Intellectual Property
• Domination of world food production by a few companies
• Increasing dependence on Industralized nations by developing countries
Ethics
• Violation of natural organisms' intrinsic values
• Tampering with nature by mixing genes among species
• Objections to consuming animal genes in plants and vice versa
• Stress for animal
Labeling
• Not mandatory in some countries (e.g., U. States)
• Mixing GM crops with non-GM confounds labeling attempts
GM crops
Crops can be given extra genes for new and
useful characteristics. They are genetically
modified (GM). What characteristics
might be useful in
crops?  pest resistance
 frost resistance
 disease resistance
 herbicide resistance
 drought resistance
 longer shelf life
Pest-resistant crops
Potatoes can be genetically modified so they are toxic to
pests, such as the Colorado beetle.
The gene for a
powerful bacterial
toxin is added to
the potato plant.
If the beetle tries
to eat the potato
plant, it is killed
by the toxin.
Frost-resistant crops
Crops can be genetically modified so they are
resistant to adverse environmental conditions.
For example,
lettuces could be
genetically modified
to be resistant to
frost.
GM
nonlettuce
GM
Why are some people against the
lettuce
development and use of GM crops?
Plants with extra vitamins
Rice can be genetically modified to make beta-carotene, a
substance that is converted into vitamin A in the body.
The colour of the rice is
an indication of how
much more betacarotene it contains.
The GM rice is called
‘Golden Rice’ and is
being developed to
help fight vitamin A
deficiency and
blindness in developing
countries.
The First Clone!
Her name was Dolly.
Now cats may have more
than nine lives. The
company that funded the
first successful cloning of a
domestic cat, has gone
commercial. You can clone
your own kitty. Your cost?
U.S. $50,000 each.
"Cc," the first-ever cloned cat shown
here at seven weeks old with Allie, her
surrogate mother.
The cat was cloned by transplanting DNA from
Rainbow, a female three-colored tortoiseshell (or
calico) cat into an egg cell whose nucleus had been
removed, and then implanting this embryo into Allie,
the surrogate mother.
"CC's coat color suggests that she is a clone, and a
genetic match between CC and the donor mother
confirms this," the researchers say.
How does it work?
In cross pollination (think Mendel’s peas), we are
combining two traits to get a mixture of results
In genetic engineering, a single gene, a half page recipe in the 52-thousand-page
set of recipe books, can direct the plant to make new traits or remove them
Recombinant DNA
• The ability to combine
the DNA of one
organism with the
DNA of another
organism.
• Recombinant DNA
technology was first
used in the 1970’s
with bacteria.
1982
• Humulin® is approved for the treatment of
diabetes.
Step 1 Isolation of Foreign DNA
• Involves finding the gene you
want to sequence’
• Then cutting it out of the
chromosome (DNA) with
restriction enzymes (sticky
ends).
Restriction Enzyme Example
• TaqI
T CGA
AGC T
• Cuts between T and C
• Leaves sticky end CG
Recombinant DNA
Step 2 Insertion of DNA into Bacterial Plasmid
• Cut the plasmid (DNA) with
restriction enzyme.
• Insert gene (DNA) of interest
into the plasmid, forming
recombinant DNA.
Step 3 Transformation
• Insert recombinant plasmid
into bacteria.
• Bacteria produced with the
recombinant DNA expresses
the gene of interest.
Transformed Bacteria
With Fluorescence
Genetically Modifying Organisms
http://www.hhmi.org/biointeractiv
e/genetic-engineering
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Golden Rice Debate
https://www.youtube.com/watch?
v=Ayv_EYi43E8
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Transformation of Bacteria
Transformed
Bacterium
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BINARY FISSION
• Asexual Reproduction
– Copies chromosome
– Attach to cell’s plasma
membrane
• DOUBLING THEIR
NUMBERS EVERY 20
MINUTES
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Distinguishing between transformed and nontransformed cells:
• Typically involves incorporating an antibiotic
resistance gene in the plasmid and then
plating the cells on a medium containing that
antibiotic.
• Only the transformed cells are resistant, so
only they can grow on the medium.
Grow on Selective Medium
Transformed Bacteria
With Fluorescence
Transformed Bacteria
Growth w/o Fluorescence
No Transformation
NO Growth
No Transformation
Growth
pGlo – Gfp
Green fluorescent protein
Fluorescent
• In the laboratory,
fluorescence is easily
achieved by exposing the
protein to long range UV
light or “ black" light.
• The fluorophore absorbs
light in the UV-B region
(395 nm.. plus a smaller
absorbance peak at 470
nm)
• It emits light (fluoresces)
at 509 nm, which is in the
green part of the visible
spectrum
Gfp and Land Mines
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Neal Stewart at the
University of North Carolina
is developing plants that can
detect land mines
Plants could be ideal
biosensors for land mines as
seeds would be spread
widely and evenly in a
suspect field
The gene that can announce
the presence of land mines
is gfp
The gene will be expressed
in the presence of a land
mine
Green Fluorescent Protein
and Plants
GFP and mice
Glo fish
• Fluorescent zebra fish
were specially bred to
help detect
environmental pollutants.
By adding a natural
fluorescence gene to the
fish, scientists are able to
quickly and easily
determine when our
waterways are
contaminated
pGlo
• Transformation of E. coli
with the pGlo plasmid
• Ori
• Gene for Gfp
• The plasmid contains the
genes for the Arabinose
promoter
• The plasmid contains the
genes for ampicillin
resistance
• If the bacterium uptakes
the plasmid it should glow
in response to long range
uv light
Arabinose operon
• araO1 is an operator site. AraC binds to
this site and represses its own
transcription. In the presence of arabinose,
however, this site helps to activate
expression of the PBAD promoter.
Trasnformation movie
P Glo transformation
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Pick one colony from the starter plate.
Use the sterile loops
Swirl the loop in ice cold CaCl2 ( experimental)
Place in ice for 10 minutes ( Your tubes will be incubating when you enter
the room). I have found that a longer incubation period here increases the
yield of transformants
While the tubes are incubating label your plates
LB AMP these plates eliminate bacteria that do not have gene for antibiotic
resistance to ampicillin
LB/AMP? Ara- These plates contain Arabinose and Ampicillin
These are called the selection plates. The Arabinose will induce the gene
to be turned on
LB- Luria Broth Agar – all bacteria should grow on this agar
Heat Shock
• Leave cells in
transformation
solution on ice for ten
minutes
• Transfer to water bath
at 42oC for 90
seconds
• Return cells to ice
Recovery and Plating
• Incubate bacteria in Luria Broth for
10 minutes before plating in Petri
Dish
• Plate your bacteria
+ pGlo – LB AMP and LB/Amp/Ara
- pGlo – LB and LB/AMP