Скачать презентацию Chapter 6 Contd More examples Genetically Modified Crops
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Chapter 6 Contd. More examples Genetically Modified Crops (GMOs) Includes a range of food: Rice, Corn, Soybeans, Cotton, Sweet Potato, Fish, Chickens, and Cows
WHAT ARE GENETICALLY MODIFIED CROPS? Genetically modified crops are those whose traits and phenotypes have been genetically modified by taking altered DNA and inserting it into the target crop. Genetically modified crops are produced from genetically modified organisms which have had their genome altered through genetic engineering techniques.
Background In 2003, about 167 million acres in 18 countries were planted with transgenic crops, the principal ones being herbicide and insecticide resistant soybeans, corn, cotton, and canola. In 2003, countries that grew most of the transgenic crops were the United States (63%), Argentina (21%), Canada (6%), Brazil (4%), and China (4%), and South Africa (1%). Growth is expected to increase in developing countries.
Gun Shot
Antisense
Protoplast Fusion • Makes use of callus cells to generate protoplast. • Protoplast from two different species can be fused together with PEG to form a hybrid plant. • This technique been used to create ‘Broccoflower’.
Traits that can be engineered to crops § § § Insect resistance Disease resistance Herbicide resistance Enhanced nutrients Produce medicinal products
1. Insect Resistant Crops Results of insect infestation on Bt (right) and non-Bt (left) cotton bolls.
Bt Cotton in India
Bt Corn
2. Herbicide Resistance § Weed-infested soybean plot (left) and Roundup Ready® soybeans after Roundup treatment. § Gene that codes for glyposate digesting enzyme is added to soybeans
3. Disease resistant crops Papaya have been engineered to resist the papaya ringspot virus. Genes that code for protein coat was added, thus given the crop immunity
4. Biopharmaceuticals from crops Recombinant Tobacco can be used to make human proteins, such as human serum albumin. Crops could also produce vaccines and plantbodies.
FLAVR SAVR TOMATO The first commercially successful genetically modified crop was the Flavr Savr tomato in 1992 by Calgene Inc. , The tomato was made resistant to rotting by adding an antisense gene which interferes with the production of the enzyme polygalacturonase, the enzyme which is responsible for cell walls softening during the fruit ripening.
GM Tomato http: //www. public. iastate. edu/~rhetoric/105 H 16/cofp/tmrcofp. htm l
Golden Rice In Golden Rice two genes have been inserted into the rice genome by genetic engineering, to account for the turned-off genes. This intervention leads in turn to the production and accumulation of β-carotene in the grains. The intensity of the golden colour is an indicator of the concentration of β-carotene in the endosperm (refer text book for Golden rice and its nutritive value)
…Golden rice
Genetic Vaccine • The most common virus used in plant transfection is the Tobacco Mosaic Virus. • This can be used as a vector to transmit genetically modified DNA into plant cells for expression much like the Agrobacter. This is sometimes referred to as a plant vaccine.
Banana Vaccine Bananas have emerged as the best candidate to deliver a bite-sized vaccine for hepatitis B virus (HBV) to millions of people in developing countries, according to an article scheduled for the June 1 issue of ACS' Biotechnology Progress Researchers so far have successfully engineered several plants -- including banana, potato, lettuce, carrot, and tobacco -- to produce HBV vaccines.
Broccoflower
World regulation of GMs The Cartagena Protocol on Biosafety was formulated in 2000. Concerned to standardize the movement of GMOs across international boundaries. As of 4/17/06, signed by 132 countries. The US has not signed yet. Protesters at Cartagena meeting supporting movement to reduce amount of GM foods across borders.
COUNTRIES THAT PRODUCE GMO’S
Laws Regulating GMOs Since the advent of biotechnology the United States and Europe have sought to control the development, approval and production of GM crops. Currently the US and the EU have different strategies, with the US becoming more liberal and the European Union becoming more stringent. The US and Canada frequently dispute the EU over GM policies that affect trade.
U. S. GM policy In the last decade the laws regulating the production of transgenic products. The United States has developed and approved several GMOs for commercial production. Broccoflower Bt Cotton Bt Soybeans Flavr Savr Grapple
EU GMO policy The European Union’s regulations on the producion, release, and consumption of GMOs has become more stringent in the last decade. Few GM products have been approved, and the production, import and domestic sale of GM products.
Economic conflicts Canadian GM corn has not been approved by the EU, so the import has ceased much to the benefit of Australian and Central European corn farmers. GM corn from the US has not been approved. Argentina corn growers that grow approved corn have taken over the US’s share Brazil is now the leading supplier of soybeans to the UK, not the US.
Drawbacks to GMOs GMO = great money obligation- the science behind GM is expensive. Bt genes may affect soil fertility. Preservation of species biodiversity- gene flow to non -GM organisms. Food as a political weapon: - Developing countries could be faced with : “force feeding”: Either buy the $50 M GM crop face starvation. or
Controversies Scientist believe that it is interfering with nature by taking genes from organisms and placing them in different organisms. Unnecessary stress placed on animals through genetically modifying crops with animal DNA. Some countries including USA do not believe it is necessary to place labels whether the product is genetically altered or not.
Benefits Economic Enviromental Society
Economic Less pesticides used Less herbicides used Less work done by farmer More commercially viable products
Enviromental Less farmland used so more land is returned to nature Biodiversity increases on farm Friendly use of herbicides and pesticides
Society At the moment the only viable way to feed the growing human population on less farmland Impoversied countries are getting the neutrients they need.
Current research • Insert Selenium into edible plants, a proven cancer fighter. • Absorption of elemental Selenium at a faster rate than plants absorb naturally. Wild plant Astragalus bisulcatus naturally accumulates selenium but is poisonous to humans and Thomas Sors (Ph. D) research would be to abstract certain genes from the plant to fight cancer.
References (Websites) http: //dragon. zoo. utoronto. ca/~jlm-gmf/T 0401 B/history. html http: //www. whybiotech. com/index. asp? id=1254 http: //www. webelements. com/webelements/text/Se/key. html Mc. Cown, Brent. Transgenic Plants. " 10 April 2006.
. . More References http: //www. foe. co. uk/resource/briefings/gm_c rops_food. pdf http: //en. wikipedia. org/wiki/Flavr_Savr http: //dragon. zoo. utoronto. ca/~jlmgmf/T 0101 A/Enzyme. html http: //www. who. int/foodsafety/publications/bi otech/20 questions/en/ http: //pewagbiotech. prg/resources/factsheets/d isplay. php 3? Factsheet. ID=2 http: //www. csa. com/discoveryguides/gmfood/ overview. php
. . References-click on each link to more about GM around you!!! Dunwell, J. M. 1999. Transgenic crops: The next generation, or an example of 2020 vision. Ann. Bot. 84: 269 -277. "Text of the Protocol. " Cartagena Protocol on Biosafety. 06 -2 -2006. Convention on biological diversity. 17 -April-2006
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