How are GM Crops made? Old method Old Method – Cross Breeding Same species Takes many generations.
Thousands of years Teosinte Modern corn How are GM Crops made? Old method
How are GM Crops made? New method Transgenics Can move genes from any living organism. GM Cotton resistant to boll weevil Cotton
Advantages of GM Foods Increased production Decreased pesticide use Improved shelf-life More land available for farming Flavr Savr Tomato
Disadvantages of GM Foods No label Allergy risk? Mixing of genes with wild relatives Safe for human consumption
Bt Crops Bacillus thuringiensis is a common soil bacteria. Produces a protein - toxic to certain insects (not humans) Toxin coats intestine and larvae starve.
Bt Crops Sprayed to control both beetle, moth, and butterfly larvae. European Corn Borer causes $1 billion in crop damage each year.
RoundUp Ready RoundUp is an herbicide used to control weeds RoundUp Ready crops are resistant to RoundUp.
RoundUp Ready Concerns Is it safe for the environment? –No-till land has increased 35% –Estimated 1 billion tons of soil erosion prevented –5% increase in herbicide use
How Are GM Crops Made Isolate Gene Place gene in “gene cassette” –Promoter – tells cell “beginning of gene” –Transgene – codes for protein –Terminator – tells cell “end of gene” –Gives gene “context” otherwise it’s “just DNA” PROMOTERTRANSGENETERMINATOR
How Are GM Crops Made Transfer Gene to organism –Viruses or bacteria to infect cells (agrobacteria) –Gene Gun
What are we doing in lab? Bring in a food item made of corn or soy Isolate DNA PCR Run and analyze Gel
What is our PCR detecting? Tubulin – found in all plants; cytoskeleton CaMV35S promoter – strong promoter from Cauliflower Mosaic Virus; used in many gene cassettes
Thinking Ahead Will we be able to detect what trait our GM Food has? What is the purpose of detecting tubulin? No, detecting the promoter, not the transgene which codes for traits. Control – helps us know if we successfully isolated DNA and set up PCR.
Why do we need to modify foods in the first place? ?
Access to food Need to feed millions of starving people Need to feed millions of starving people Only 10% of land is “arable” (can produce crops) Only 10% of land is “arable” (can produce crops)Others?
How are crops genetically modified? Classical genetics (cross-breeding) vs. transgenics http://www.teachersdomain.org/resources/ tdc02/sci/life/gen/breeding/index.html http://www.teachersdomain.org/resources/ tdc02/sci/life/gen/breeding/index.html
How common is GM Food? 63% of all land used to grow GM crops is in U.S.
How common is GM Food? Number of acres used for GM Farming is increasing world wide.
How common is GM Food? In U.S. (2004) - 45% of corn (38% in WI) - 85% of soybeans (82% in WI) - 76% of cotton
How are transgenics made? http://cls.casa.colostate.edu/TransgenicCrops/ animation.html http://cls.casa.colostate.edu/TransgenicCrops/ animation.html Determine which gene, Isolate DNA, cut out gene, paste gene into a plasmid, gene gun to transfer DNA into plant cells, clone to produce more transgenic plants
What are some issues related to GM-Foods? What types currently exist? How much of our crops are currently GM? How much of the food in the store? How would we know if something is GM or not?
What are some issues related to GM-Foods? Is GM Food safe to eat? How safe is it? Safe for the environment? Does it result in more or less use of pesticides? More or less use of herbicides? Who determines if it is safe or not?
What are some issues related to GM-Foods? Can the genes escape into nature? http://www.teachersdomain.org/resources/tdc02/sci/life/gen/salmon/index.html
Which are GM traits are most commonly used? Virus Resistance –Papaya, beets Roundup Ready (herbicide resistance) –Canola, cotton, soybeans, corn Bt (pest resistance) –Cotton, corn, potatoes –Harvest of Fear Video Clip Harvest of Fear Video ClipHarvest of Fear Video Clip
Bt crop - concerns Can insects develop resistance to Bt? –Yes, but that’s true for non-GM insect-resistant crops as well. –Recommended that Bt crops be alternated with regular crops.
Bt crops - concerns Is Bt safe for the environment? 69.7 million pounds less pesticide used in 2005. Fewer “non-target” insects such as monarch butterflies are killed compared to spraying. Can Bt crops still kill non- target insects?
Bt concerns? Is Bt safe for humans? –FDA considers Bt to be safe for human consumption. Digested quickly. –Humans have been exposed to Bt for many years.
RoundUp Ready Concerns Can the herbicide- resistance genes move by pollen? –“Superweeds” –Yes, but true for non- GM herbicide-resistant crops as well. –Not a trait that will allow it to outcompete in wild areas
General GM Food Concerns Are GM Foods safe for the environment? –World’s 1950 grain output = 692 million tons –World’s 2003 grain output = 1.9 billion tons 170% increase Same number of acres –Would need 1.8 billion additional hectares of land to produce same amount of grain by 1950’s methods.
General GM Foods Concerns Allergens –What if new gene encodes a protein causes allergic reactions and/or death in people? –How would you predict if a food might contain a new allergen?
RoundUp is considered “Friendly” - It is virtually nontoxic to mammals, birds, fish, and insects - - It exhibits essentially no pre-emergence activity. It won't prevent plants in your garden from germinating. - - It exhibits essentially no residual soil activity even when applied at high rates. Roundup binds tightly to soil particles and doesn't move on or in the soil to affect untreated plants nearby - - It breaks down quickly into natural materials such as carbon dioxide and nitrogen - - It does not penetrate the woody stems of trees, shrubs, or grapevines - - Finally, the most important feature, once inside the plant, glyphosate inhibits a key enzyme found only in plants and bacteria EPSP synthase.