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Genetically Modified Foods: Myths and Realities Genetically Modified Foods: Myths and Realities Source: www.accessexcellence.org Source: www.accessexcellence.org

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Page 1: Genetically Modified Foods: Myths and Realities › ~super7 › 24011-25001 › 24951.pdf · Genetically Modified Foods: Myths and Realities Source: : ... GM foods are better analyzed

Genetically Modified Foods: Myths and Realities

Genetically Modified Foods: Myths and Realities

Source: www.accessexcellence.orgSource: www.accessexcellence.org

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Miracle foods for a hungry world.....Miracle foods for a hungry world.....

http://scope.educ.washington.edu/gmfood/http://scope.educ.washington.edu/gmfood/

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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?

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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:

Page 5: Genetically Modified Foods: Myths and Realities › ~super7 › 24011-25001 › 24951.pdf · Genetically Modified Foods: Myths and Realities Source: : ... GM foods are better analyzed

⇒ 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?

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⇒ 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

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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

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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

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⇒ 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”

Page 10: Genetically Modified Foods: Myths and Realities › ~super7 › 24011-25001 › 24951.pdf · Genetically Modified Foods: Myths and Realities Source: : ... GM foods are better analyzed

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

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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

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Agrobacterium: nature’s genetic engineerAgrobacterium: nature’s genetic engineer

Agrobacterium is the causative agent of gallsAgrobacterium is the causative agent of galls

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Nucleus

Plant cell

Plant’s DNA

Introducing genes using the Ti plasmidIntroducing genes using the Ti plasmid

T-DNA

Agrobacterium

Ti plasmid

NEW GENE

Page 14: Genetically Modified Foods: Myths and Realities › ~super7 › 24011-25001 › 24951.pdf · Genetically Modified Foods: Myths and Realities Source: : ... GM foods are better analyzed

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

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Here’s how it looks in the laboratoryHere’s how it looks in the laboratory

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A plant with a new gene addedA plant with a new gene added

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⇒ 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

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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

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The story of papayaringspot virus

The story of papayaringspot virus

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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

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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

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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

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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

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⇒ 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

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Golden riceGolden rice

Rice with vitamin A and ironRice with vitamin A and iron

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⇒ 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?

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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

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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

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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

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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

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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?

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⇒ 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?

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⇒ 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

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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?

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⇒ 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

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Why are attitudes toward GM foods so negative?Why are attitudes toward GM foods so negative?

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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