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Need a Job???. David Threadgill’s Lab is looking for a work-study student… Responsibilities include general lab maintenance (app. 10 to 20 hours a week) Perks include an AWESOME working environment with a lot of cool people and interesting research!
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Need a Job??? David Threadgill’s Lab is looking for a work-study student… Responsibilities include general lab maintenance (app. 10 to 20 hours a week) Perks include an AWESOME working environment with a lot of cool people and interesting research! Call David Threadgill at 843-6472 for more info Visit our website at http://152.19.39.101/
Genetic Engineering of Plants & Animals
Genetic Engineering: Changing the genetic make-up of an organism using biotechnological methods GE: Genetically Engineered Foods GM: Genetically Modified Foods GMO: Genetically Modified Organisms Transgenic Crops
Common Applications of GE • Make crops, livestock, etc. more profitable • -- Pest resistance, herbicide resistance, shortened growth period, traits preferred by consumer • Make medically important substances easy to obtain • -- Enzymes, proteins, tissues • Make transgenic animals for medical and biological research • -- Disease models, gene function studies
Examples of GE crops • Starlink and Bt Corn: Resistant to common pests • Tomatoes: “Flavr- Savr” Slow softening ripe tomatoes • Herbicide resistant soybeans and cotton: “Round-up” Ready • Tear-free onions (development in progress)
How do you make a GE crop? Cold tolerance • Identify gene that encodes trait of interest • Transfer DNA into plant cells via bacteria or a gene gun. • The DNA integrates into the plant’s chromosomes • Culture the modified plant cells to grow many cells with the desired trait • Grow the plant cells in a special culture that causes the cells to differentiate • The plantlets are transferred from the laboratory culture to soil Cold tolerance Delivery and Integration Culture and Differentiate http://www.agwest.sk.ca/sabic_index_tp.shtml
Bacillus thuringiensis (Bt): Soil bacterium that produces a toxin targeting the gut of common pests of corn, such as the European corn borer Different forms of the toxin (Cry proteins) can be used to target specific pests Can be up to 99% effective Insects can develop resistance Starlink corn scare
Flavr-Savr Tomatoes: Antisense Technology Isolate DNA Polygalacturonase (PG): an enzyme expressed during ripening causing depolymerization of the pectin fraction of the cell wall, which results in softening of ripe tomatoes. PG Coding GP Noncoding Add CMV promoter GP The PG gene was identified in the tomato and inserted into a plasmid in such a way that a PG antisense transcript is produced The antisense transcript binds the PG sense mRNA blocking access of the translational machinary eliminating 99% of the PG product Delivery and Integration Antisense suppression of PG
GE Animals Quick growing Salmon Healthier Pork Allergy-proof Cats
“Super Salmon” A growth hormone in Salmon is normally produced only in warm temperatures An antifreeze protein was discovered in flounder that is expressed only in cold temperatures The control elements from the flounder gene were placed upstream of a copy of the salmon growth hormone gene The salmon with the transgene grow during the warm and cold seasons
Healthier Pork FAD2 is found in spinach and converts saturated fats into linoleic acid (an unsaturated fat) The gene was placed in a pig’s genome The transgenic pigs contain 20 percent less saturated fat This is the first time a planet gene has been inserted into an animal genome
Allergy Proof Cats Cat allergies are thought to be caused by a single protein in the cat’s skin and saliva.An allergen-free cat could be available by the year 2003, costing somewhere in the region of $1000 The researchers aim to take cat cells and knock out the gene that produces the problem protein, replacing it with an inactive version.The cell’s nucleus will then be put into a cat egg cell, that has had its own genes removed, creating an embryo that can be implanted into a surrogate mother.
Making Medicine though Genetic Engineering Turning animals (and plants) into pharmaceutical factories Goat’s Milk Anti-cancer tomatoes Pigs for organ harvest Malaria Free Mosquitoes
Goat milk drug production Insert gene for antithrombin III (anti-coagulate) into goat genome with necessary signals for secretion into milk Purify protein from goat’s milk Drug prevents blood clotting in patients with antithrombin deficiency (homozygous recessive)
Cancer Preventative Tomatoes Lycopene is a carotenoid that gives tomatoes their red color It is an antioxidant; carotenoids capture electrically charged oxygen molecules that can damage tissue People that eat lots of fruits and vegetables containing lycopene have less breast and prostate cancers A yeast gene is expressed in the tomato that stabilizes the lycopene and results in 3X the amount of lycopene
Pigs for Organ Harvesting • Xenotransplantation is limited by immune response of recipient • The rejection response occurs when human antibodies attach to sugar molecules on the surface of the transplanted pig organ's cells, killing the cells • The gene that produces this sugar molecule, called a-1,3-galactosyltransferase (GGTA1) has been eliminated in a line of miniature swine • The swine also have organs approximately the same size as human organs
Malaria-Free Mosquitoes Malaria is a deadly parasite transmitted to humans via mosquitoes SM1 gene: prevents malaria from entering salivary gland from mosquito gut SM1 was placed under control of a promoter controlled by feeding in the mosquito genome Mosquitoes with SM1 were unable to transmit malaria to mice To effectively eliminate transmission transgenic mosquitoes must be able to survive as well or better than wildtype mosquitoes
Are GE products safe? Usually involve random insertion into genome Includes promoters (CaMV) and enhancers that can influence activity of nearby native genes (may activate normally unactive genes such as toxins) Gene inserted is usually for a foreign protein that could have undesirable effects in addition to the desired effects Many of the proteins have not previously been eaten in food -- how will consumer be affected? Fusion proteins / protein folding
Environmental Issues Cross pollination / breeding with wild species Production of “super weeds” Impact on other species (such as the monarch)
Have you eaten GM Food? • The US and Canada produce 82% of the world’s GM food. • In 1999 almost one-quarter of our nation's food and fiber crops were genetically engineered • US GE Crops: 57% of U.S. soybeans, 38% of U.S. corn, 65% of U.S. cotton, 4% of U.S. potatoes, and over 50% of the U.S. and Canadian canola crop • 60% of processed foods sold in grocery stores contain at least a trace of GM ingredients
What do people think about GE? US, China, and Canada: ~75% of consumers approve Europe and Japan: Less accepting of GM food (less than 20% approve) But…knowledge about GE is lacking in the general public European Survey: Would you buy GM food?
Animals for Research Transgenic Mice, Plants, Flies, etc. Transgenic animals can be created to study gene function and/or human disease genes Can make a variety of changes to yield information -- Null alleles (insert an antibiotic resistance gene in exon) -- Point mutations -- Deletion mutations (eliminate part of a gene or protein) -- Duplications -- Hypomorphic mutation – changes level of gene expression -- Controlled expression of gene in different spatial or temporal context
NEO NEO Construct to Disrupt Gene of Interest (GOI) Transform and select Test chimeras for germ-line transmittance of brown genome GOI Look for chimeric progeny ES cell from brown mouse Let ES cells divide Inject into blastocyst from white mouse and implant in pseudopregnant female
Links of interest... Trangenic Pets: http://www.transgenicpets.com/ News Collections: http://www.newscientist.com/hottopics/gm/ http://www.agbiotechnet.com/topics/Database/index.asp http://greennature.com/article299.html Overview: http://members.tripod.com/c_rader0/gemod.htm Labeling GM foods: http://www.thecampaign.org/ Pros and Cons: http://scope.educ.washington.edu/gmfood/ Activist Page: http://archive.greenpeace.org/~geneng/