- Slides: 24
Genetically Modified Foods
What is a Genetically Modified (GM) Food? Foods that contain an added gene sequence n Foods that have a deleted gene sequence n Animal products from animals fed GM feed n Products produced by GM organisms n
Why are foods genetically modified? t Genetic engineering offers a rapid and precise method of altering organisms as compared to traditional methods that are slow and inaccurate.
Examples of GM food ð Vegetables ð Tomatoes ð Potatoes ð Rice ð Cheese ð Meat Their genes are usually modified to make the crops pest or herbicide resistant
Examples of GM food n 1994: Flavr Savr© tomato – the first approved GM food product - tomato genes are usually modified to delay ripening and softening 5
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? Its quite simple, REALLY!!!
How can DNA be moved from one organism to another? ►Find an organism with the desired trait ►Isolate the gene sequence that codes for the desired trait ►Insert the gene sequence into the genome of the plant cell
How can DNA be moved from one organism to another? ►Allow the genetically altered cell to grow into a plant ►Allow the plant to propagate
How can DNA be moved from one organism to another? Ù 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.
Role of GM Foods in EMs n Very important for developing countries/EMs – – n By 2050 pop. 9 b food strategy for next 20 yrs Need more food, as such hunger and starvation 3 m deaths/year in Africa solely relating to hunger 3 options: aid/food, money/funds, provide GM foods: foods Rapid, accurate, ↑ yield, ↓labor, ↑shelf-life
Advantages of GM Foods… n Pest resistance – Crop loss due to insets financial loss to farmers – So, farmers use tons of pesticides/fertilizers annually – GM eliminates pesticides and thus ↓ cost of production n Disease resistance – Viruses, fungi, bacteria plant diseases – GM crops resistance to these diseases n Cold resistance n Frost can destroy sensitive seedlings – Antifreeze gene from cold fish tobacco and potatoes
Advantages of GM Foods n Drought resistance – More population ↑ land for housing, ↓ land for farming – Land unsuited for plant cultivation Africa, dessert – GM crops grow in draughts or ↑ salt-content soil n Nutrition – – n Single crop (rice) cannot give all the nutrition needed Lack vitamin A blindness common in EMs GM food: golden rice has Vitamin A (beta-carotene) GM food: with enhanced iron is underway, Europe? Pharmaceuticals – Edible vaccines in tomatoes and potatoes – Easier to ship, store, administer than traditional injections
Criticism of GM Organism/Foods…
Criticism of GM Foods… n Environmental hazards – Unintended harm to other organism n Difficult to design toxin kills crop-damaging pests, not other insects – Reduced effectiveness of pesticides n Develops resistance DDT – Gene transfer to non-target species n n Cross-breeding Transfer of herbicide resistance from crops to weeds The “superweeds” will then have herbicide tolerance as well Solution – Create buffer zone
Criticism of GM Foods… n Human health risks – – – n Allergenicity We already have allergies to peanuts and other foods… Introducing gene may create more allergies Unknown effects on human health However, proposal to introduce a gene from Brazil nuts into Soyabeans was abandoned On the whole, with the exception of possible allergenicity, scientists believe that GM foods do not present a risk to human health!
Criticism of GM Foods n Economic concerns – Lengthy and costly process – May be patented n n Monsanto, Novartis, Dow, Du. Pont hold patents for GM crops Make substantial profit by exporting it to EMs – Farmers from developing countries/EM cannot afford – More gap between rich and poor n Other invention discouraged/stopped – Suicide gene technology n n Only one growing per season Next time would produce sterile seeds that do not germinate
Governments and GM Foods… 2009: 25 countries
Governments and GM Foods n n n Europe: Anti-GM protests (Austria, France, Hungary) Japan: GM testing is mandatory. Customers for organic USA: FDA GM foods are substantially equivalent to natural food, so not subject to FDA regulations – GRAS Generally Recognized As Safe n n India: No policy yet for GM ↓ poverty Brazil: Some states have banned GM crops – ↑Smuggle to compete with grain-exporting countries n Africa: EU opposes the use of GM in Africa – S. Africa, Sudan, Zimbabwe have GM laws; Kenya Act 2009 n Argentina: Indifferent n New Zealand: NO GM Foods grown here!
GM Food Labeling n n No need to label same wrt to nutrition Europe and Japan Mandatory – – – n 1% contamination of unmodified products with GM foods Consumers have the right the know the information Let consumers decide but no choice Reduced sales, so processors do not sell GM foods EU has disguised policy of protectionism Canada and US Voluntary – Mandatory for Non-GM foods – Let consumers decide more choices
Homework Assignment ð How do you feel about GM foods? Are they beneficial or harmful? w Compare and contrast articles of your choice w Write a short report on your views about GM foods.
Possible Risks of GM Foods t t Insects might develop resistance to pesticideproducing GM crops Herbicide-tolerant crops may crosspollinate weeds, resulting in "superweeds"
Possible Risks for GM Foods Certain gene products may be allergens, thus causing harm to human health There may be unintended harm to wildlife and beneficial insects Photo courtesy of T. W. Davies, Cal. Acad. of Sciences.