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transgenics. What is a Genetically Modified (GM) Food?. Foods that contain an added gene sequence Foods that have a deleted gene sequence Animal products from animals fed GM feed Products produced by GM organisms. Common GM Foods. Vegetables Tomatoes Potatoes Rice Cheese Meat.
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What is a Genetically Modified (GM) Food? • Foods that contain an added gene sequence • Foods that have a deleted gene sequence • Animal products from animals fed GM feed • Products produced by GM organisms
Common GM Foods • Vegetables • Tomatoes • Potatoes • Rice • Cheese • Meat
Step 1: Identify the gene of interest • Roundup (glyphosate) kills plants by targeting the enzyme EPSP synthase • Allele of bacterium EPSP synthase was almost completely insensitive to Roundup (glyphosate)
Step 2: Amplify Gene using PCR • Using bacterial DNA as a template, Polymerase Chain Reaction creates millions of copies of DNA segment (EPSP synthase) in a test tube • The high concentration product can be used to “clone” the gene into a plasmid • PCR animation
Step 3: Clone PCR Fragment into Plasmid • Restriction enzymes (scissors) are used to cut your PCR fragment (EPSP synthase) and your plasmid • Ligase (paste) is used to seal the two linear fragments and make a circle again
SOME RESTRICTION ENZYMES • EcoRI • HindIII • MstIII • Animation • Leave “sticky ends” • Found in Bacteria Naturally • 3)Recognition Sites - PALINDROMES
Step 4: Transformation • Plasmid is reintroduced into a bacteria • The bacteria will reproduce and make more of your recombinant plasmid • Will also make the protein if it is needed!
Step 5: Insert the plasmid into the Plant genome and Grow it up!
Step 6: Test Your Transgenic • New corn is resistant to Roundup • Can spray crops with Roundup and kill everything but your transgenic
List of genetically modified crops and their altered traits.
Transgenic Cattle • Dairy cows carrying extra copies of two types of casein genes produce 13% more milk protein • Not only will this make the milk more nutritious, it would allow for less milk to make more cheese • Currently the milk from these animals is under FDA review • The important difference between this & other transgenics is that the DNA added is not foreign
Transgenic Fish • Tilapia • Salmon/trout • Catfish • Can grow up to 6 times faster than wildtype fish • Most have extra copies of growth hormone (GH) gene http://www.nature.com/nbt/journal/v19/n6/images/nbt0601_500a_I1.jpg
Transgenic Goats • GTC Biotherapeutics has received approval to sell human anti-thrombin (ATryn) purified from goat’s milk in Europe
GloFish • Originally developed in Singapore as a way to monitor water pollution • The normally black-and-silver Zebrafish was turned green or red by inserting various versions of the GFP gene • Glofish are on sale throughout the US except in California • Glofish retail for about $5 per fish. Normal zebrafish cost around one tenth of the price