Transcript Genetically Modified Organisms

Genetically Modified
Organisms
Chapter 15 (ibook)
GMO: Genetically Modified
Organism
• GMO: organism whose genome has been
engineered in the laboratory in order to favour
the expression of desired physiological traits or
the production of desired biological products.
• NY Times – Genetically Modified Food
Navigator
• Britannica article
• Britannica GMO background
More New Vocab
• Biotechnology – process of manipulating
organisms, cells, or molecules to produce a specific
products.
• Recombinant DNA - DNA produced by combining
DNA from different sources.
• Transgenic organism – containing genes from
another species
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host that carries the inserted DNA from one or more organisms = genetically
modified organism
Genetic Engineering/Modification
• Selective Breeding (hybridization vs. inbreeding)
• Ex: dog breeds
• 1849 -1926 Luther Burbank (botanist) developed more than
800 varieties of plants via hybridization
Hybridization – crossing dissimilar individuals to bring
together the best of both.
Inbreeding – maintains desirable characteristics in a line
of organisms
• Associated risk: increase chance that a cross will bring
together 2 recessive alleles for genetic defect.
Crop
Desired trait
(color)
Cross breeding
Pear
Apple
Offspring
Cross breeding
Best results
New
offspring
Desired
result
Fig. 12.11, p. 273
Biotech Crops in the United States
[from Wikipedia]
Fig. 9-10 here
The Objectives of Genomics
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Disease resistance
Drought tolerance
Frost tolerance
Salt tolerance
Improved nutritional value
Incorporate human vaccines
The Problems with Genomics
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Environmental concerns
Not considered safe by all consumers
Not affordable in all countries
Major player in the future of agriculture
Might keep food production in pace with
population growth
Environmental Problems
• Pest resistance to genetically engineered
toxin
• Broad spectrum impact on non-target
species
• “Super weeds”
• Contamination (decreasing natural
variation)
Food Safety Issues
• Proteins cause allergic responses
• Antibiotic resistance to human pathogens
• Plant produces new toxic substances
Summary: GMF Controversy
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Unexpected plant mutations create higher toxin levels
Introduce new allergens into foods
Lower nutritional value
Don’t help feed world’s hungry
Reduce effectiveness of natural pesticides
Resistant genes passed on through pollination to wild relatives =
super weeds
Increased herbicide use on resistant crops
Increased costs of food to cover devp. & patenting of GMF
Rapid evolution of pesticide resistant insects.
Killing beneficial insects – monarch butterfly
Introducing chemicals into soil killing soil organisms
Irreversible and unpredictable genetic & ecological effects
Polymerase Chain Reaction
• Amplifies a selected
section of DNA quickly
– Provides LOTS of DNA to
work with and analyze
• PCR animation
• PCR tutorial
• PCR song
35S Promoter Gene
• This is a “marker” found in many GMO’s
– from cauliflower mosaic virus; allows modified
genes to enter original modified plant cells
• Wild Type : no marker = (-)
• Round-Up Ready: yes marker = (+)
• Your food sample:
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(-) result = not a GMO
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(+) result = yes a GMO!
Tubulin Protein
• Plant protein found in all plants, therefore,
the gene for this protein should be found in
all plant DNA samples.
• (-) Your sample is missing plant DNA!
• (+) Your sample contains captured plant DNA!
Results you should get:
• Wild Type Soy Bean:
(-) 35s
(+) Tubulin
• Round-Up Ready Soy Bean:
(+) 35 s
(+) Tubulin
• Your Food Item:
(???) 35s
(+) Tubulin unless your food is really over-processed!
Gel Electrophoresis
• Physically separate different sized
fragments through an agarose gel using
an electrical current
• Tutorial 1
• Tutorial 2 - Work through 4 Discovery Modules
• Tutorial 3- Go to “Manipulation” then “techniques”
then “sorting and sequencing”