1. Gene Technology Chapter 9
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2. Genetic Engineering Experiments Polymerase Chain Reaction
Outline
Restriction Enzymes
Genetic Engineering Experiments
Polymerase Chain Reaction
DNA Fingerprinting
Genetic Engineering and Medicine
Genetic Engineering of Crop Plants
Genetic Engineering of Farm Animals
Cloning
Ethical Issues
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3. Scientific Revolution
Genetic Engineering refers to the process of moving genes from one organism to another.
Having major impact on medicine and agriculture.
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4. Can pair with any other DNA fragment cut by same enzyme.
Restriction Enzymes
Restriction enzymes that bind to specific short sequences (typically 4 to 6 nucleotides) of DNA.
Restriction enzymes make their incisions so that two single-stranded ends are complementary in sequence (sticky ends).
Can pair with any other DNA fragment cut by same enzyme.
Joined by DNA ligase.
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5. Restriction Enzymes
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6. Genetic Engineering Experiment
Cleaving DNA To Produce Fragments
Can sort using electrophoresis.
Producing Recombinant DNA
Insert fragments into plasmids or viral DNA.
Cloning
Plasmids or viruses serve as vectors.
Screening
Locate specific sequences.
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8. Preliminary Screening
Eliminate from clone library any clones not containing vectors.
Finding Gene of Interest
Use cloned genes from base pairs with complementary sequences on another nucleic acid (Probe).
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9. Other Genetic Techniques
Polymerase Chain Reaction (PCR)
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10. Other Genetic Techniques
Formation of cDNA
Entire gene is transcribed by RNA polymerase forming primary transcript.
Introns must be cut out, and remaining fragments stitched together to form processed mRNA.
Cytoplasmic mRNA has only exons. Reverse transcriptase is used to make an DNA version of isolated mRNA (cDNA).
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11. Other Genetic Techniques
DNA Fingerprinting
Using DNA probes to characterize DNA isolated from an individual.
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12. Genetic Engineering and Medicine
Diabetes is a condition where body is unable to control levels of sugar in the blood because a critical protein, insulin, cannot be made.
Genes encoding many medically important proteins are now introduced into bacteria.
Insulin
Anticoagulants
Factor VIII
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13. Genetic Engineering and Medicine
Piggyback Vaccines
Traditionally, vaccines were made by killing the disease agent. Now a modified virus displays piggybacked surface proteins, to which immune system makes antibodies.
Gene Therapy
One way to cure many genetic diseases is to give the affected person a working copy of the defective gene.
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14. Piggyback Vaccine for Herpes Simplex
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15. Genetic Engineering of Crop Plants
Pest Resistance
Reduce use of chemical pesticides.
Herbicide Resistance
Lowers cost of producing crop.
Reduced plowing conserves topsoil.
More Nutritious Crops
Golden Rice
Iron and Vitamin A
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16. Transgenic Golden Rice
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17. Genetic Engineering of Crop Plants
Potential Risks: Is Eating Them Dangerous?
Roundup Resistant soybeans:
Inhibits Aromatic Amino Acid production to make crop easier to grow.
Humans don’t make any
Changes nutritional character to improve nutrition.
Potential allergies
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18. Genetic Engineering of Crop Plants
Potential Risks: Harmful to the Environment?
Bt corn was genetically engineered to contain insect-killing toxin to combat corn-borers, but also killed butterflies.
Must weigh pesticide-induced losses to genetically-modified losses.
Introduced genes may pass to wild relatives.
Gene flow occurs naturally.
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19. Genetic Engineering of Farm Animals
Monsanto received federal approval to make its recombinant bovine somatotropin (BST) commercially available to dairy farmers.
Consumers worry about transfer through cow’s milk.
This transfer does not occur, and effects to humans would be negligible, if any.
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20. Mammary cells and egg cells surgically combined in January 1996.
Cloning
Dolly
Mammary cells and egg cells surgically combined in January 1996.
Mammary cells inserted inside the covering around the egg cell.
Brief electrical shock applied.
29 dividing embryos transplanted into surrogate mother sheep, and on July 5, 1997, one sheep gave birth to a lamb.
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21. Value of Gene Therapy vs: Personal identity issues.
Ethical Issues
Fear of human cloning at the heart of ethical dilemmas (Technical reasons should not prove an overwhelming obstacle).
Value of Gene Therapy vs:
Personal identity issues.
Increased genetic uniformity may cause future disease problems.
Inability to adapt to changing environmental conditions.
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies

22. Genetic Engineering Experiments Polymerase Chain Reaction
Review
Restriction Enzymes
Genetic Engineering Experiments
Polymerase Chain Reaction
DNA Fingerprinting
Genetic Engineering and Medicine
Genetic Engineering of Crop Plants
Genetic Engineering of Farm Animals
Cloning
Ethical Issues
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies

23. Copyright © McGraw-Hill Companies Permission required for reproduction or display
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