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Genetically Modified Foods. Ms. Gaynor Honors Genetics. What are GM organisms?. A result of technology that has altered the DNA of living organisms (animals, plants or bacteria) Other terms that mean the same thing: Genetically engineered Transgenic Recombinant DNA (rDNA) technology.
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Genetically Modified Foods Ms. Gaynor Honors Genetics
What are GM organisms? • A result of technology that has altered the DNA of living organisms (animals, plants or bacteria) Other terms that mean the same thing: • Genetically engineered • Transgenic • Recombinant DNA (rDNA) technology
How does this differ from Mendel and his peas? GM vs. Selective breeding Selective breeding -slow and imprecise -modification of genes that naturally occur in the organism GM -very fast and precise -can introduce genes into an organism that would not occur naturally!
What is a Genetically Modified (GM) Food? • Foods that contain an added gene sequence • Or foods that have a deleted gene sequence • Animal products from animals fed GM feed (food) • Products produced by GM organisms • VIDEO #1 • http://www.teachersdomain.org/resource/tdc02.sci.life.gen.breeding/
Why are foods genetically modified? • Genetic engineering offers a rapid and precise method of altering organisms as compared to traditional methods that are slow and inaccurate.
Common GM Foods • Vegetables • Tomatoes • Potatoes • Rice • Cheese • Meat • Fruit VIDEO #2 http://www.teachersdomain.org/resource/tdc02.sci.life.gen.btcorn/
Why do it? Examples • Rice is not high in essential nutrients Modification: • ADD (+) daffodil genes and a bacterium = beta-carotene content drastically increased • ADD (+) genes from a french bean = double the iron content. • Tomatoes- Introduce genes to increase shelf life.
How is genetic modification possible? • The components of DNA are the same in all organisms. • Sequences that code for proteins can be moved from one organism to another.
How can DNA be moved from one organism to 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
A vector can carry DNA. The vector can be a pellet from a gene gun. Viruses and bacteria also can be utilized to transfer genes. How can DNA be moved from one organism to another?
Possible Benefitsof GM Foods • Easing of world hunger • Development of crops that can be grown in different soil • Development of drought resistant crops • Development of salt-tolerant crops • Development of crops that make more efficient use of nitrogen and other nutrients • Faster maturation time • Longer shelf life/less waste
Possible Benefits (con’t) • Reduced use of pesticides and herbicides • Development of pest resistant crops • Reduced herbicide use is better for the environment and reduces costs for farmers
Possible Benefits (con’t) • Improved crop quality • Development of frost resistant crops • Development of disease resistant crops • Development of flood resistant crops • Save $$ (more profits) • Improved nutritional quality • Development of foods designed to meet specific nutritional goals VIDEO #3 http://www.teachersdomain.org/resource/tdc02.sci.life.gen.salmon/
Who makes sure GM foods are safe? • Government agencies regulate GM foods • GM foods in the United States are required to be labeled only if the nutritional value is changed or a new allergen is introduced.
Possible Risks of GM Foods • Insects might develop resistance to pesticide-producing GM crops • Herbicide-tolerant crops may cross-pollinate weeds, resulting in "superweeds"
Possible Risks (con’t) Help me! I live in the corn belt! • Certain gene products may be allergens causing harm to human health • There may be unintended harm to wildlife and beneficial insects • Natural selection disrupted
Possible Risks (con’t) Human Safety • Creation of biological weapons Access and Intellectual Property • Domination of world food production by a few companies and developing countries • $$$ and ownership
Possible Risks (con’t) Ethics • “Playing God” • Tampering with nature by mixing genes among species Labeling • Not mandatory in some countries (ex: Canada and the United States) • Mixing GM crops with non-GM confounds labeling attempts