Transcript I. Genetic Engineering D. Drawbacks • Opponents emphasize failures of technology, potential environmental harm “Frankenfood” “Farmageddon” Harm to native species through competition • • 1. • 2. Transgenic organisms could be superior competitors • Potential route to.

I.
Genetic Engineering
D.
Drawbacks
•
Opponents emphasize failures of
technology, potential environmental harm
“Frankenfood”
“Farmageddon”
Harm to native species through competition
•
•
1.
•
2.
Transgenic organisms could be superior competitors
•
Potential route to extinction for native species
Damage to beneficial insects
•
3.
Ex – Evidence that ladybugs and lacewings suffer (shorter lifespan,
reduced reproduction) when fed aphids and caterpillars that had fed on
GM potatoes and corn, respectively
Damage to soil community
•
•
4.
Certain GM crops could reduce activity of soil fungi and microbes
Negative impact on nutrient cycling in the soil
Release of resistance genes
•
•
5.
Could potentially lead to “super weeds” if resistance genes get
transferred to weedy species
Could harm non-GM agriculture, including organic farming through pollen
drift
Upset natural balance of ecosystems
•
Could result from release of GMOs or hybridization between GMOs and
native species
•
Ex – GM rape can crossbreed with wild turnips, passing herbicide
tolerance to offspring
•
Potential solution = “Terminator technology”
I.
Genetic Engineering
E.
Trends
•
125 GM agricultural plants approved for
growth in the U.S. (ISAAA)
•
Most designed to
1) Reduce pest damage
2) Confer resistance to herbicides, pesticides,
viruses, other pathogens
3) Reduce crop spoilage
Genetically modified crop traits tested
in developed countries, 1987–2000
I.
Genetic Engineering
E.
Trends
•
•
•
US grows ~48% of GM crops worldwide
(acreage basis)
2012: corn 88%, cotton 94%, soy 93% GM
Other major growers of GM crops
1)
2)
3)
4)
5)
Brazil
Argentina
India
Canada
China
www.ers.usda.gov/data-products/adoption-of-genetically-engineered-crops-in-the-us/recent-trends-in-ge-adoption.aspx
I.
Genetic Engineering
F.
Examples
Bollgard® and Bollgard II® Cotton
1.
•
•
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•
Both strains express insecticidal protein isolated from
Bacillus thuringiensis (Bt)
•
Safe – Farmers can spray with Bt toxin and still label
produce as organic
•
Low toxicity to most non-target organism types
•
Low persistence – breaks down readily
Bollgard II® has stacked traits to enhance effectiveness
•
Controls bollworms, budworm
Year 2000 – United States averages
•
Cotton fields planted with Bollgard ® sprayed 3.9
times less often vs. conventional fields
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Reduced total pesticide use by 2.7 million pounds
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Pest control cost less - $15.43/acre
Higher production - 37 pounds/acre
•
•
Higher profit - $39.86/acre
Concern – Development of resistance by insect pests
I.
Genetic Engineering
F.
Examples
2.
Golden Rice
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•
a.
b.
GM rice containing genes that produce beta-carotene
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Can be converted to vitamin A
•
Vitamin A deficiency (VAD) may cause weakened immune
systems, partial to total blindness, and increased chance of
death
•
VAD causes 350,000 cases of blindness and has been
linked to 1 million+ deaths each year
Highly controversial
Proponents
•
Reduce incidence of blindness and other VAD related
health disorders
•
1/2 lb of rice/day will keep VAD symptoms away
Opponents
•
Nutritional deficiencies will prevent people from absorbing
beta-carotene from rice
•
Concentrations of beta-carotene in rice are low, and an
average woman would need to eat 16 lbs of golden rice a
day to get 100% of daily requirement
•
Alternatives like leafy green vegetables or unpolished rice
are better, cheaper sources of vitamin A
•
Western corporations are trying to control rice production
I.
Genetic Engineering
F.
Examples
3.
Future GM crops
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SmartStaxTM corn
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Pest resistant, herbicide tolerant
Bt rice
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Pest resistant
High omega-3 soybeans
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Enhanced nutrition
RR Sugarbeets*
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Herbicide tolerant
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2007: <10% of US
•
2009: 95% of US
Blue roses
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Ornamental
I.
Genetic Engineering
G.
Benefits and Risks
1.
Benefits
•
a.
b.
Accelerated improvement of crop strains
Elevated yields, either per plant or per acre
•
Usually involves inserting growth factor
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Plants grow larger, faster or both
•
Con – Accelerated growth may alter chemical
composition  Allergies, digestive problems, etc.
Accelerated maturation process
•
Increased yield per acre, more crops per year
•
Con – Plants produce different compounds at
different life stages
•
Young plants tend to produce more irritants and
toxins (self defense)
•
Potential to cause digestive or allergic problems
I.
Genetic Engineering
G.
Benefits and Risks
1.
Benefits
c.
d.
Increased resistance to disease, pests, toxins
•
Reduced losses  Greater yield
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Reduced application of chemicals
•
Con – Potential transfer of resistance genes to
weedy plant species through pollination
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Less problematic in areas where crop plants don’t
have wild relatives
•
Con – Development of resistance in pests
Increased longevity of harvested produce
•
Resistance to spoilage
•
Ex – Potato engineered with bacterial gene for
antifungal properties
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Helps potatoes to stay in storage without rotting
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Con – Chemicals that resist decomposition likely to
be more difficult to digest
I.
Genetic Engineering
G.
Benefits and Risks
1.
Benefits
e.
f.
Increased resistance to cultural extremes
•
Ex – Insertion of Arctic flounder antifreeze protein
genes into strawberry
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Confers greater frost resistance and better fruit
storage properties
•
Con – Potential transfer of antifreeze genes to weedy
plant species
Increased nutritional value
•
Ex – High starch potato that absorbs less oil when
cooking (low fat potato chips)
•
Ex – Canola oil (Laurical®) with healthier
composition
•
Con – Unknown effects of eating modified foods
•
Ex – Insertion of Brazil nut gene into soybeans to
increase protein content
•
Many people allergic to Brazil nuts
I.
Genetic Engineering
G. Benefits and Risks
1.
Benefits
g.
Reduced dependence on chemical fertilizers
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More efficient growth  lower use of fertilizer
•
American farmers spend >$12 billion a year on
chemical fertilizers
•
50% or more of fertilizer applied to crops is not
absorbed and enters runoff  water pollution
•
Con – Transfer of genes for greater growth
efficiency to weeds could be disastrous
•
Con – Substitution of dependence on big
western agribusiness
I.
Genetic Engineering
G.
Benefits and Risks
2.
Risks
a.
Unexpected effects
•
May or may not be beneficial
•
Ex – Klebsiella planticola (soil bacterium) engineered
to transform plant residue into ethyl alcohol (fuel)
•
GM strain in soils produced EtOH, leading to
poisoning of grasses and decrease in populations of
beneficial mycorrhizal fungi
•
Ex – Pseudomonas putida (bacterium) engineered to
degrade 2,4-D (herbicide)
•
Breakdown products highly toxic to fungi, including
mycorrhizae
•
Ex – Bacillus thuringiensis (Bt) toxin may bind to soil
particles, slowing degradation and maintaining
toxicity for longer than expected