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Genetically Modified Crop Plants
Genetically Modified Crop Plants
Genetic Engineers CanModify Food
• Transgenic organisms are produced when a gene from one organism is incorporated into the genome of another
• The more popular term for transgenic organisms is GMO, for genetically modified organism
• GM foods means genetically modified
GMO examples
Genetically Modified Food
Inserting the Gene
Inserting the Gene
Inserting the Gene
Pros to Creating Genetically Modified Food
Pros to GMOs
• Better resistance to weeds, pests, disease
• Better texture, flavor, nutritional value
• Longer shelf life, easier shipment
• Better yield, more efficient use of land
• Less herbicides and other chemicals
• Essential if we are to feed the world
Cons to Creating Genetically Modified Food
Cons to GMOs
• They can have harmful effects on the human body– It is believed that consumption of these
genetically engineered foods can cause the development of diseases which are immune to antibiotics.
– These foods are new inventions, not much is not known about their long term effects on human beings. As the health effects are unknown, many people prefer to stay away from genetically modified foods
Cons to the Environment
• Creates “super weeds”
• Creates “super bugs”
• Effects natural ecosystems
Bt and the Monarch butterfly
• Bacillus thuringiensis (Bt) is a soil bacterium that produces insecticidal toxins.
• Genes from Bt can be inserted into crop plants to make them capable of producing an insecticidal toxin and therefore resistant to certain pests.
• Bt corn can adversely affect non-target insects if they are closely related to the target pest, as is the case with Monarch butterfly
Genetically Modified Foods in the U.S. Diet
• Over half of all food in U.S. market contain at least some GM foods
– Most soybeans grown are modified for herbicide resistance
– GM corn – an ingredient in most processed foods – is common as well
– GM canola and cottonseed oils are used in a huge range of food products
FDA Regulations
• Manufactures must get FDA approval for an food not generally recognized as safe (GRAS), including new genetically engineered food substances
• The FDA declared milk from rBGH cows safe for consumption in 1993
How Are GM Foods Evaluated for Safety?
• The EPA must approve all GM crops• GM foods can cause allergic
reactions (8% of us are allergic to foods)
• Newly inserted genes may also encode proteins that prove to be toxins
Genetic Engineering/ DNA Technology
3 types of Cloning Technologies:
1. Recombinant DNA Technology/ DNA Cloning
2. Reproductive Cloning
3. Therapeutic Cloning
Cloning the bovine growth hormone (BGH) gene
Recombinant DNA Technology/DNA Cloning
Cloning a Gene
• Cloning means making many copies of a gene
Recombinant DNA Technology/DNA Cloning
1. Remove the Gene of Interest2. Cut the Plasmid DNA3. Insert the Gene into the Bacterial
Plasmid4. Insert the Recombined Plasmid
into the Bacterial Cell5. Let the Bacteria Reproduce
1. Remove the gene of interest (ex: BGH gene) using restriction enzymes
Restriction enzymes cut DNA at specific sequences called palindromes . . .
Restriction Enzymes Leave “Sticky Ends”
Restriction Enzymes
• The unpaired bases on the sticky ends form bonds with any complementary bases with which they come into contact
2. Cut the Plasmid DNA with the Same Restriction Enzyme
3. Insert the Gene of Interest into the Bacterial Plasmid
(The bacterial plasmid is also cut with the restriction enzyme, leaving sticky ends)
4. Insert the Recombined Plasmid into a Bacterial Cell
5. Let the Bacteria Reproduce
Other Proteins Made by DNA Cloning:
•Insulin for diabetics•Clotting factors for hemophiliacs
Basic Versus Applied Research
Basic research
• no profit motive or direct commercial application – generally government funded
Applied research
• immediate and profitable application – generally privately funded
Reproductive Cloning/Cloning Entire Organisms
Reproductive Cloning
• Technology used to generate an animal that has the same nuclear DNA as another curretly or previously existing animal
Steps in Nuclear Transfer
Steps in Somatic Cell Nuclear Transfer
Results of Nuclear Transfer Experiments
There were 277 failures before this nuclear transfer technique succeeded;
Reproductive Cloning
Dolly was successfully born in 1997
Reproductive Cloning
• Dolly was put to sleep at the age of 6 in 2003
• She was suffering from arthritis and a progressive lung disease
• These are usually only seen in old sheep
Other Organisms Reproductively Cloned
Mouse
Cow
Goat
Mule
Horse
Rabbit
Cat
Pig
Dog
Rat
Deer
Why Do Reproductive Cloning?
Have We Reproductively Cloned Humans?
Opposition and Support of Human Cloning
What do YOU think?
Therapeutic Cloning/ Embryo Cloning
• Instead of cloning entire organisms, there is therapeutic cloning
• Stem cells are induced to turn into specific tissue cells
Therapeutic Cloning
The Human Genome Project
Sequenced the entire human genome
Goals of The Human Genome Project
Organisms With Genome Sequenced
Rhesus Macaque
Fruit Fly
Zebra fish
Potato
Many organisms have genome projects that have either been completed or will be completed shortly, including
:
•Humans•Neanderthal•Haemophilus influenzae, a bacterium•Common House Mouse•Brown Rat•Common Chimpanzee•Rhesus Monkey•Domestic Chicken•Domestic Cat•Domestic Dog•Common fruit fly•Baker's yeast
Many organisms have genome projects that have either been completed or will be completed shortly, including
•Red bread mold,
•Thale Cress
•Rice
•Common Wheat
•Corn
•Poplar Tree
•E. coli bacteria
•SARS virus
•Nematode worm
•Zebra fish
•Tomato
•Potato
•Western Honey Bee
•Grapevine
•Spanish flu virus
The Human Genome Project
• These were used as model organisms in genetic studies
• These model organisms contain genes that are the same as human genes
Gene Testing
DNA Chips
Pros and Cons of Gene Testing
Gene Therapy
• Once the genetics are worked out, gene therapy can be researched
• Replacing defective genes with functional ones
– Germ line gene therapy in embryos– Somatic cell gene therapy in
individual somatic cells in affected tissues
Gene Therapy
• Germ Line Gene Therapy
• Somatic Cell Gene Therapy
Gene Therapy
• Non disease causing virus is genetically engineered with the functioning gene that is needed in SCID patients
• The virus infects the immune cells and the immune cells get the functioning gene
Gene Therapy
Gene Therapy
• Treatment for SCID (severe combined immunodeficiency)
• Gene therapy in cells of the immune system
Somatic Gene Therapy
• is not widely used
• Is only for single gene disorders with cells that can be removed, engineered and then replaced in the body
Somatic Gene Therapy
• The condition may still be passed to offspring, because somatic cell gene therapy does not treat all the cells in the body
Setbacks to Gene Therapy
1.Treat Cancer
2. Gene Therapy to treat inherited form of blindness is successful!
Recent Successes in Gene Therapy
