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Genetically Modified Food. Genetically Modified Foods Which of the following does not qualify as a genetically modified food? A)Angus cattle B)Guernsey.

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Presentation on theme: "Genetically Modified Food. Genetically Modified Foods Which of the following does not qualify as a genetically modified food? A)Angus cattle B)Guernsey."— Presentation transcript:

1 Genetically Modified Food

2 Genetically Modified Foods Which of the following does not qualify as a genetically modified food? A)Angus cattle B)Guernsey dairy cows C)Rhode Island red chickens D)Broccoli E)Corn

3 F) None of the above! There are almost no foods you eat that come from naturally occurring species Farmers have been selectively breeding, cross- pollinating, etc. for thousands of years

4 Basic Genetics Dominant & Recessive Genes Someone might express a dominant gene but carry a recessive gene Recessive genes from both sides can appear in subsequent generations Plants (or animals or people) can be modified by selecting for desirable traits

5 Plant Breeding by Trial & Error Natural Selection – Darwin Artificial Selection –Used for millennia for crop improvement –Select best product for future use Artificial selection has led to much more profitable and edible crops –Higher food to waste ratio –Land produces higher yields

6 Modern Plant Breeding Gregor Mendel’s laws of inheritance 1857 – peas (tall, short, smooth, wrinkled, etc.) Mendel’s theories accepted ~ 1900 Crossing plants with thousands of genes (45,000 – 56,000 genes in rice) Improves crop yield but undetermined consequences because of large number of genes involved Improves edibility of crops – break down plant’s natural defenses against predators (chemicals which may be toxic or allergenic to humans)

7 Plant Genetic Modification (GM) Introduce gene or genes artificially Plants can be described as “transgenic” Began in late 1970s – development of DNA manipulation Gained knowledge of how to cut DNA molecules at particular points and glue back together – recombinant DNA technology

8 GM Process Propagate selected DNA through bacteria propagation Cut & splice plant genes into plasmids and then propagate in Escherichia coli (human gut bacterium) Used to modify plant characteristics – higher yield, more edible, disease resistant, pest resistant, etc. First used in pharmaceutical industry to make recombinant human insulin – approved by FDA in 1981

9 Genetic Modification of the Potato Genetically Modified Crops, Nigel Halford, 2003

10 Advantages of GM Precision – involve only individual genes that are desirable Genes can act on only a specific part of plant or a particular portion of its life cycle Safety of protein produced by gene can be studied prior to use in GM program Improved crop yields Improved crop characteristics Reduce pesticide use – insect resistant and/or herbicide resistant crops

11 Disadvantages of GM Invest more time & money than program of random mutations Barriers and restrictions to GM crop development – regulations in some countries Safety????

12 GM Statistics In 2001, 6% of total world agriculture were GM crops > 50% of world’s soybean crop is genetically modified Countries growing GM crops: US, Canada, Argentina, Uruguay, Mexico, Spain, Bulgaria, Ukraine, Romania, China, South Africa, Australia

13 Golden Rice The vitamin A-producing gene is taken out of a red pepper and put into rice Advantage: Could save millions of children world-wide from blindness

14 Siberian Tomatoes (Strawberries, too) The anti-freeze-producing gene is taken out of a flounder and put into tomatoes Advantage: Tomatoes that can be shipped at lower temperatures, less rotting, less waste, and more profit for tomato growers

15 B.t. Corn An insecticidal protein from the bacteria Bacillus thuringiensis is put into corn Advantage: Corn is protected from pests, so chemical pesticides are not necessary

16 In development: Banana Vaccine Viral proteins for infectious diseases such as Hepatitis B will be put into bananas Advantage: Ability to efficiently vaccinate people world-wide

17 Potential Safety Concerns 1.Pleiotropy: genes have multiple functions, especially when they work in conjunction with other genes  We may transfer genes that have other functions we don’t want  The genes may develop new functions when they interact with a new genome

18 Potential Safety Concerns 2.Plasmids: functions (especially undesirable ones) may transfer to other organisms in the environment 3.Pollination: When plants spread seeds, other farms could pick up transgenic traits without realizing it

19 Potential Safety Concerns Since transgenic foods haven’t been around long, nobody can study the long-term effects of eating these foods yet And these are just the safety issues–there’s a lot more to consider!

20 Questions for you Are the benefits of golden rice worth the risks? Why or why not? Are the benefits of Siberian tomatoes worth the risks? Why or why not? How do you decide what type of genetically modified food is worth the risk of eating? The EU currently bans the importation of live genetically modified plants but does import genetically modified foods. Is this good policy?

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