Transcript GMOsChapter20

Genetically Modified Organisms
• Organisms that are modified by the
alteration or introduction of
foreign DNA, in order to produce a
desired trait or effect
• Plants are the most common
targets (transgenic crops):
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Pest resistance (e.g. Bt-hybrid corn)
Drought resistance
Cold-tolerance
Shelf-life
Ripening
Nutritional value
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Bt-hybrid vs. non-Bthybrid corn
Creation of a GMO
• Genetic material is artificially combined,
usually in the form of circular pieces of
DNA called plasmids
– Plasmids contain not only DNA coding for
the trait of interest, but also DNA that
controls the expression and selection of the
trait
• Delivery methods:
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Agrobacterium tumefaciens
Ballistics or gene gun
Electroporation
Chemical and/or heat treatment
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http://sustain.no/virtue/newsletter/00_08/currtrant/more-info/plasmid.jpg
Transformation
• Process by which genetic material carried by an individual cell
is altered by the addition and expression of foreign DNA
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The DNA may or may not be incorporated into the genome
• Electrical, thermal, mechanical and chemical and biological
methods
• Transformed cells are identified by some type of marker or trait
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Antibiotic resistance
Color
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Transformation using Agrobacterium tumefaciens
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Bacterial species
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Normally infects plants and
causes crown-gall disease
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Very efficient at inserting DNA
into plant cell genome – Bingo!
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Symbiotic Relationship
• T-DNA leads to synthesis of:
– Auxin – plant hormone causes cell proliferation
– Opines – serve as a source of energy for A. tumefaciens
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Step 1. Engineer Agrobacterium with
your favorite gene(s)….
Ti = Tumor inducing
Step 2. Disarm the genes that cause crown
gall disease
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Human impact on
ecosystems
Kingston fossil plant Ash spill
(2008)
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Carbon cycle
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The instability of a fossil fuel economy
Pros
Cons
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Novel innovations for alternative
energy
Wind energy
Cellulosic ethanol
Hydrogen fuel
cells
Solar energy
Electric cars
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Group activity:
Rank the following alternative energy
technologies from most promising (best) to
least promising (worst)
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Biodiesel
Hydrogen fuel cells
Electric cars (Lithium ion batteries)
Cellulosic ethanol
Wind
Geothermal
Solar
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One problem with electric cars
Chevy Volt
Lithium ion battery
Nissan Leaf
Lithium is also a finite resource that is mined from salt
flats
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Lithium salt mining in Bolivia
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>50% (estimated) of the world’s
lithium lies in Salar de Uyuni
Evo Morales:
President of
Bolivia
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Ethanol as a renewable fuel?
MTBE
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Government support for more
E85 pumps (85% ethanol, 15%
gasoline)
• Government announced
Friday 10,000 more E85
pumps in the next 5 years
• "Flex-fuel pumps will
give Americans a choice
to purchase domestically
produced renewable
transportation fuels.“- US
Agriculture secretary Tom
Vilsack (Friday, April 8, 2011)
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Overview of Brazil sugarcane
ethanol
• ~8 million hectares
• Supplies 40% of
Brazil
transportation fuel
• Brazil wants to
expand to 40
million hectares
• Currently only the
sugar part of cane
is used (14% of
mass)
• Brazil will likely
become an ethanol
powerhouse
1 hectare = 2.47
acres
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Plants are mostly made up of sugars
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Why
Cellulosic
Ethanol?
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Why Switchgrass?
• Native grass to
US
• Perennial crop
• Requires little to
no fertilizer
• Can be grown
on marginal land
• Use hay bail
machinery
• Farmer income
• No erosion
• Large fleet of
E85 vehicles on
road
http://www.wbir.com/news/local/story.aspx?storyid=112598
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• Pilot biorefinery
Miscanthus giganteus stand growing for 10
years never fertilized or irrigated
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Ethanol: The bad news
• Food vs. fuel vs. feed agricultural land
• Absorbs water – 2006- present many complaints
about engine damage with E10 (found to exceed)
• EtOH requires 42X more water than gasoline
• Energy density is 2/3 that of gasoline
• Logistics of moving large amounts of biomass
• Calculations of cost-benefit are VERY
complicated
– However, technology is so IMMATURE that these
numbers are meaningless
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Algae as a renewable source of ethanol and
biodiesel
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Algae for ethanol and biodiesel:
infrastructure costs too great
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Survival of the human species depends
on our ability to capture energy in a
way that is sustainable
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We should start planting fields of switchgrass
everywhere so we can fuel our cars on
renewable fuel
• Without talking to your neighbor, do you agree
or disagree?
• Write all of your reasons for your position (one
per sticky note) No talking!
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It is BETTER for the U.S. government to
invest more money into DEFENSE than into
ENERGY
• Without talking to your neighbor, do you agree
or disagree?
• Write all of your reasons for your position (one
per sticky note) No talking!
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