Genetically Genetically Modified Modified

FoodsFoodsMs. GaynorMs. Gaynor

Honors GeneticsHonors Genetics

What are GM What are GM organisms?organisms?

A result of technology that has altered A result of technology that has altered the DNA of living organisms (animals, the DNA of living organisms (animals, plants or bacteria)plants or bacteria)

Other terms that mean the same thing:Other terms that mean the same thing: Genetically engineeredGenetically engineered TransgenicTransgenic Recombinant DNA (rDNA) technologyRecombinant DNA (rDNA) technology

How does this differ from How does this differ from Mendel and his peas?Mendel and his peas?

GM vs. Selective breedingGM vs. Selective breedingSelective breedingSelective breeding-slow and imprecise-slow and imprecise-modification of genes that -modification of genes that

naturally occur in the organismnaturally occur in the organismGMGM-very fast and precise -very fast and precise -can introduce genes into an -can introduce genes into an

organism that would not occur organism that would not occur naturally! naturally!

What is a Genetically What is a Genetically Modified (GM) Food?Modified (GM) Food?

Foods that contain an added gene Foods that contain an added gene sequencesequence

Or foods that have a deleted gene Or foods that have a deleted gene sequencesequence

Animal products from animals fed Animal products from animals fed GM feed (food)GM feed (food)

Products produced by GM Products produced by GM organismsorganisms

VIDEO #1VIDEO #1 http://www.teachersdomain.org/resource/tdc02.sci.life.gen.breeding/

Why are foods Why are foods genetically modified?genetically modified?

Genetic engineering offers a Genetic engineering offers a rapid and precise rapid and precise method of method of altering organisms as altering organisms as compared to traditional compared to traditional methods that are slow and methods that are slow and inaccurate.inaccurate.

Common GM FoodsCommon GM Foods VegetablesVegetables TomatoesTomatoes PotatoesPotatoes RiceRice CheeseCheese MeatMeat FruitFruit

VIDEO #2http://www.teachersdomain.org/resource/tdc02.sci.life.gen.btcorn/

Why do it? ExamplesWhy do it? Examples Rice Rice is not high in essential nutrientsis not high in essential nutrients

Modification:Modification: –ADD (+) daffodil genes and a ADD (+) daffodil genes and a

bacterium = beta-carotene content bacterium = beta-carotene content drastically increased drastically increased

–ADD (+) genes from a french bean ADD (+) genes from a french bean = double the iron content.= double the iron content.

Tomatoes- Introduce genes to Tomatoes- Introduce genes to increase shelf life. increase shelf life.

How is genetic How is genetic modification possible? modification possible?

The components of The components of DNA are the same DNA are the same in all organisms.in all organisms.

Sequences that Sequences that

code for proteins code for proteins can be moved from can be moved from one organism to one organism to another.another.

How can DNA be moved How can DNA be moved from one organism to from one organism to

another?another?Find an organism with the desired trait (“gene of interest”)

Isolate the gene sequence that codes for the desired trait

Use restriction enzymes to “cut” the DNA out

Insert the gene sequence into the genome of the plant or animal cell

How is this done? How is this done? Transgenic tomatoesTransgenic tomatoes

How can DNA be moved How can DNA be moved from one organism to from one organism to

another?another? A vector can carry A vector can carry

DNA. DNA. The vector can be a The vector can be a

pellet from a gene pellet from a gene gun. gun.

Viruses and Viruses and bacteria also can be bacteria also can be utilized to transfer utilized to transfer genes.genes.

Possible BenefitsPossible Benefitsof GM Foodsof GM Foods

Easing of world hungerEasing of world hungerDevelopment of crops that Development of crops that

can be grown in different can be grown in different soilsoil

Development of drought Development of drought resistant cropsresistant crops

Development of salt-Development of salt-tolerant crops tolerant crops

Development of crops that Development of crops that make more efficient use of make more efficient use of nitrogen and other nutrientsnitrogen and other nutrients

Faster maturation timeFaster maturation timeLonger shelf life/less wasteLonger shelf life/less waste

Possible Benefits Possible Benefits (con’t)(con’t)

Reduced use of Reduced use of pesticides and pesticides and herbicidesherbicides►Development of Development of

pest resistant crops pest resistant crops ►Reduced herbicide Reduced herbicide

use is better for the use is better for the environment and environment and reduces costs for reduces costs for farmers farmers

Possible Benefits Possible Benefits (con’t)(con’t) Improved crop qualityImproved crop quality

Development of frost Development of frost resistant crops resistant crops

Development of disease Development of disease resistant cropsresistant crops

Development of flood Development of flood resistant cropsresistant crops

Save $$ (more profits)Save $$ (more profits) Improved nutritional qualityImproved nutritional quality

Development of foods Development of foods designed to meet specific designed to meet specific nutritional goals nutritional goals

VIDEO #3http://www.teachersdomain.org/resource/tdc02.sci.life.gen.salmon/

Who Uses this Who Uses this technologytechnology

Who makes sure GM Who makes sure GM foods are safe?foods are safe?

Government agencies Government agencies regulate GM foodsregulate GM foods GM foods in the GM foods in the United States are United States are required to be required to be labeled only if the labeled only if the nutritional value is nutritional value is changed or a new changed or a new allergen is allergen is introduced.introduced.

Possible Risks Possible Risks of GM Foodsof GM Foods

Insects might Insects might develop resistance develop resistance to pesticide-to pesticide-producing GM crops producing GM crops

Herbicide-tolerant Herbicide-tolerant crops may cross-crops may cross-pollinate weeds, pollinate weeds, resulting in resulting in "superweeds""superweeds"

Possible Risks Possible Risks (con’t)(con’t)

Certain gene products Certain gene products may be allergens may be allergens causing harm to causing harm to human health human health

There may be There may be unintended harm to unintended harm to wildlife and beneficial wildlife and beneficial insectsinsectsNatural selection Natural selection

disrupted disrupted

Help me! I live in the corn belt!

Possible Risks (con’t)Possible Risks (con’t)

Human Safety Human Safety Creation of biological Creation of biological

weaponsweapons

Access and Intellectual Access and Intellectual Property Property Domination of world Domination of world

food production by a few food production by a few companies and companies and developing countries developing countries

$$$ and ownership$$$ and ownership

Possible Risks (con’t)Possible Risks (con’t)Ethics Ethics

““Playing God” Playing God” Tampering with nature Tampering with nature

by mixing genes among by mixing genes among species species

Labeling Labeling Not mandatory in some Not mandatory in some

countries (ex: Canada countries (ex: Canada and the United States) and the United States)

Mixing GM crops with Mixing GM crops with non-GM confounds non-GM confounds labeling attempts labeling attempts