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Genetically Modified Foods: Myths and Realities
Genetically Modified Foods: Myths and Realities
Source: www.accessexcellence.orgSource: www.accessexcellence.org
Miracle foods for a hungry world.....Miracle foods for a hungry world.....
http://scope.educ.washington.edu/gmfood/http://scope.educ.washington.edu/gmfood/
i.cnn.net/.../10/biotech.us.europe/story.gm.jpgi.cnn.net/.../10/biotech.us.europe/story.gm.jpghttp://www.foeeurope.org/press/eric01.jpghttp://www.foeeurope.org/press/eric01.jpg
http://www.newint.org/issue320/Images/tradepic.jpghttp://www.newint.org/issue320/Images/tradepic.jpg
.....or public menace?.....or public menace?
What’s a GMO?What’s a GMO?
Are GMOs new?Are GMOs new?
Are GM foods safe to eat?Are GM foods safe to eat?
Are GM crops safe to grow?Are GM crops safe to grow?
Questions:Questions:
⇒ A GMO is a “genetically modified organism”⇒ A GMO is a “genetically modified organism”
⇒ Today this means a crop plant with extra genes⇒ Today this means a crop plant with extra genes
Question: What’s a GMO?Question: What’s a GMO?
⇒ GM means “genetically modified” ⇒ GM means “genetically modified”
Question: Are GMOs new?Question: Are GMOs new?
⇒ All human food crops are genetically modified⇒ All human food crops are genetically modified
⇒ To survive in the wild, plants must scatter seeds⇒ To survive in the wild, plants must scatter seeds
⇒ For people to harvest seeds, they have to stick⇒ For people to harvest seeds, they have to stick
Corn: a “traditional” GMOCorn: a “traditional” GMOwww.kukurydza.org.pl/images/teosinte1.jpgwww.kukurydza.org.pl/images/teosinte1.jpg
http://www.arini.ac.uk/pics/maize%202AltD.jpghttp://www.arini.ac.uk/pics/maize%202AltD.jpg
www.kukurydza.org.pl/images/teosinte1.jpgwww.kukurydza.org.pl/images/teosinte1.jpg
evolution.berkeley.edu/.../images/cornfld.jpgevolution.berkeley.edu/.../images/cornfld.jpg
http://scope.educ.washington.edu/gmfood/http://scope.educ.washington.edu/gmfood/
http://primera.tamu.edu/kcchome/homeowner/riored.htmhttp://primera.tamu.edu/kcchome/homeowner/riored.htm
Familiar genetically modified foodsFamiliar genetically modified foods
⇒ Today’s GMO a crop plant with extra genes ⇒ Today’s GMO a crop plant with extra genes
⇒ The extra genes were added using recombinant DNA techniques
⇒ The extra genes were added using recombinant DNA techniques
⇒ Changing plants with recombinant DNA techniquesis called “genetic engineering”
⇒ Changing plants with recombinant DNA techniquesis called “genetic engineering”
Making recombinant DNA
Making recombinant DNA
Foreign DNA
Plasmid
DNA is cut with EcoRI
DNA ligase
Sticky ends
Source: www.accessexcellence.orgSource: www.accessexcellence.org
Bacterial transformation
CaCl2 treatment
to permeabilizecell walls
Antibiotic sensitive bacterial cell
“Transformed“ bacterial cellSelection on bacterial growth mediumcontaining appropriate antibiotic
Add plasmid DNA
Making many copies of the recombinant DNAMaking many copies of the recombinant DNA
Source: www.accessexcellence.orgSource: www.accessexcellence.org
Agrobacterium: nature’s genetic engineerAgrobacterium: nature’s genetic engineer
Agrobacterium is the causative agent of gallsAgrobacterium is the causative agent of galls
Nucleus
Plant cell
Plant’s DNA
Introducing genes using the Ti plasmidIntroducing genes using the Ti plasmid
T-DNA
Agrobacterium
Ti plasmid
NEW GENE
NEW GENE
The new gene is integrated into the plant’s DNAThe new gene is integrated into the plant’s DNA
Nucleus
Plant cell
Plant’s DNA
Here’s how it looks in the laboratoryHere’s how it looks in the laboratory
A plant with a new gene addedA plant with a new gene added
⇒ Insect resistant plants⇒ Herbicide-tolerant plants⇒ Virus resistant plants⇒ Vitamin A- and iron-enriched rice
⇒ Insect resistant plants⇒ Herbicide-tolerant plants⇒ Virus resistant plants⇒ Vitamin A- and iron-enriched rice
Today:Today:
Molecular methods in plant improvementMolecular methods in plant improvement
The story of papayaringspot virus
The story of papayaringspot virus
http://www.apsnet.org/education/feature/papaya/Top.htmhttp://www.apsnet.org/education/feature/papaya/Top.htm
The story of papayaringspot virus
The story of papayaringspot virus
The story of papayaringspot virus
The story of papayaringspot virus
1991: First transgenic PRSV-resistant papaya plant1991: First transgenic PRSV-resistant papaya plant
1980s: PRSV-resistance project starts under direction of Dennis Gonsalves1980s: PRSV-resistance project starts under direction of Dennis Gonsalves
1992: PRSV discovered in Puna district1992: PRSV discovered in Puna district
1992: First field trials PRSV-resistant papaya plants1992: First field trials PRSV-resistant papaya plants
1994: USDA grants permission for large scale field trials1994: USDA grants permission for large scale field trials
1995-97: Approvals for release from USDA, EPA, FDA1995-97: Approvals for release from USDA, EPA, FDA
1992-1997: PRSV takes its toll; many farmers go out of business1992-1997: PRSV takes its toll; many farmers go out of business
1998: Seeds released, free of charge, to growers1998: Seeds released, free of charge, to growers
2000: Papaya industry bounces back; crop back to pre 1995 levels2000: Papaya industry bounces back; crop back to pre 1995 levels
http://www.apsnet.org/education/feature/papaya/Top.htmhttp://www.apsnet.org/education/feature/papaya/Top.htm
The story of papayaringspot virus
The story of papayaringspot virus
http://www.apsnet.org/online/feature/BtCorn/Images/healthy%20ear.JPGhttp://www.apsnet.org/online/feature/BtCorn/Images/healthy%20ear.JPG
http://dragon.zoo.utoronto.ca/~jlm-gmf/T0201A/corn1.jpghttp://dragon.zoo.utoronto.ca/~jlm-gmf/T0201A/corn1.jpg
Bt cornBt corn
Fusarium ear rot produces fumonisinsFusarium ear rot produces fumonisins
Kernel rot produces aflatoxinKernel rot produces aflatoxin
http://www.apsnet.org/online/feature/BtCorn/Images/healthy%20ear.JPGhttp://www.apsnet.org/online/feature/BtCorn/Images/healthy%20ear.JPG
http://dragon.zoo.utoronto.ca/~jlm-gmf/T0201A/corn1.jpghttp://dragon.zoo.utoronto.ca/~jlm-gmf/T0201A/corn1.jpg
Bt cornBt corn
Fusarium ear rot produces fumonisinsFusarium ear rot produces fumonisins
Kernel rot produces aflatoxinKernel rot produces aflatoxin
⇒ Nutritionally enhanced crops ⇒ Anti-cancer substances⇒ Edible vaccines⇒ Antibodies from plants⇒ Biodegradable plastics⇒ New biomaterials⇒ Disease-resistant plants⇒ Spoilage-resistant seeds and tubers⇒ Stress-resistant crops ⇒ High-yielding pseudo C4 rice
⇒ Nutritionally enhanced crops ⇒ Anti-cancer substances⇒ Edible vaccines⇒ Antibodies from plants⇒ Biodegradable plastics⇒ New biomaterials⇒ Disease-resistant plants⇒ Spoilage-resistant seeds and tubers⇒ Stress-resistant crops ⇒ High-yielding pseudo C4 rice
Tomorrow:Tomorrow:
Molecular methods in plant improvementMolecular methods in plant improvement
Golden riceGolden rice
Rice with vitamin A and ironRice with vitamin A and iron
⇒ Could GM foods contain new toxins?⇒ Could GM foods contain new toxins?
Are GM foods safe to eat?Are GM foods safe to eat?
⇒ Could GM foods cause allergies?⇒ Could GM foods cause allergies?
⇒ Is DNA safe to eat?⇒ Is DNA safe to eat?
⇒ Could antibiotic genes get into people?⇒ Could antibiotic genes get into people?
Are GM foods safe to eat?Are GM foods safe to eat?
⇒ Is DNA safe to eat?⇒ Is DNA safe to eat?
All foods contains DNA -- about a teaspoon of DNA in a pound of food All foods contains DNA -- about a teaspoon of DNA in a pound of food
Adding one gene adds roughly 1 part in a million or ~0.0001%Adding one gene adds roughly 1 part in a million or ~0.0001%
DNA is digested starting in your mouthDNA is digested starting in your mouth
Tiny fragments gets through the digestive processTiny fragments gets through the digestive process
This is always happening when we eat food This is always happening when we eat food
It doesn’t change our genes It doesn’t change our genes
Are GM foods safe to eat?Are GM foods safe to eat?
⇒ Could antibiotic resistance genes get into people?⇒ Could antibiotic resistance genes get into people?
No, DNA is broken down into tiny pieces in our digestive tractsNo, DNA is broken down into tiny pieces in our digestive tracts
⇒ Could they get into other bacteria in the gut?⇒ Could they get into other bacteria in the gut?
Bacteria take up DNA very rarelyBacteria take up DNA very rarely
Transfers to gut bacteria have been looked for, but not foundTransfers to gut bacteria have been looked for, but not found
Are GM foods safe to eat?Are GM foods safe to eat?
⇒ Could GM foods contain new toxins?⇒ Could GM foods contain new toxins?
The FDA requires chemical analyses and toxicity studiesThe FDA requires chemical analyses and toxicity studies
GM foods are better analyzed than any in human history GM foods are better analyzed than any in human history
Plants contain chemicals that are toxic -- in large amountsPlants contain chemicals that are toxic -- in large amounts
Are GM foods safe to eat?Are GM foods safe to eat?
⇒ Could GM foods cause allergies?⇒ Could GM foods cause allergies?
⇒ Allergy facts⇒ Allergy facts
Most food allergies are caused by about half a dozen proteinsMost food allergies are caused by about half a dozen proteins
Foods contain more than 100,000 different proteins Foods contain more than 100,000 different proteins
The FDA requires developers to identify allergenicity potentialThe FDA requires developers to identify allergenicity potential
A GM food is less likely to cause a problem than any new food you’ve ever tried
A GM food is less likely to cause a problem than any new food you’ve ever tried
What’s the bottom line?What’s the bottom line?
⇒ Could genes escape from crops to cause problems?⇒ Could genes escape from crops to cause problems?
Are GM crops safe to grow?Are GM crops safe to grow?
⇒ Will GM crops reduce biodiversity?⇒ Will GM crops reduce biodiversity?
⇒ Could genes escape from crops to cause problems?⇒ Could genes escape from crops to cause problems?
Gene transfer from crops to other plants is now called “gene flow”Gene transfer from crops to other plants is now called “gene flow”
Gene flow occurs between members of the same speciesGene flow occurs between members of the same species
⇒ What kinds of problems does gene flow cause?⇒ What kinds of problems does gene flow cause?
Gene flow is not a new problem in agricultureGene flow is not a new problem in agriculture
It depends on the cropIt depends on the crop
http://www.scu.edu/cas/research/images/smecology.jpghttp://www.scu.edu/cas/research/images/smecology.jpg
The monarch butterfly incidentThe monarch butterfly incident
http://www.newsroom.ucr.edu/images/releases/997_0.jpghttp://www.newsroom.ucr.edu/images/releases/997_0.jpg
Bt genes in Mexican land racesBt genes in Mexican land races
⇒ Will GM crops reduce biodiversity?⇒ Will GM crops reduce biodiversity?
⇒ Will GM crops reduce biodiversity?⇒ Will GM crops reduce biodiversity?
“To assert that GM techniques are a threat to biodiversity is to statethe exact opposite of the truth.”
“To assert that GM techniques are a threat to biodiversity is to statethe exact opposite of the truth.”
“The less focused and productive this agriculture is, the more destructive its effects will be.”
“The less focused and productive this agriculture is, the more destructive its effects will be.”
“Nothing has driven more species to extinction or caused moreinstability in the world’s ecological systems than the developmentof an agriculture sufficient to feed 6.3 billion people.”
“Nothing has driven more species to extinction or caused moreinstability in the world’s ecological systems than the developmentof an agriculture sufficient to feed 6.3 billion people.”
Peter Raven, Director of the Missouri Botanical GardenPeter Raven, Director of the Missouri Botanical Garden
Why are attitudes toward GM foods so negative?Why are attitudes toward GM foods so negative?
Does it matter whether we accept GM crops?Does it matter whether we accept GM crops?
“You people in the developed world are certainly free to debate themerits of genetically modified foods, but can we please eat first?”
-- Florence Wambugu, 2003
“You people in the developed world are certainly free to debate themerits of genetically modified foods, but can we please eat first?”
-- Florence Wambugu, 2003