Lecture 35 Transgenic Fish

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Lecture 35Transgenic Fish
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Steps for Making Transgenic Fish
Step 1. Decide Gene/Protein to Add. Step 2.
Decode Protein and Translate to cDNA Code.
cDNA
Protein
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Steps for Making Transgenic Fish
Step 3. Prepare Gene Construct.
Gene Construct
Protein Gene
Promoter Gene
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Steps for Making Transgenic Fish
Step 4. Insert Construct into Bacterial Plasmid.
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Steps for Making Transgenic Fish
Step 5. Insert Plasmid in Bacterial Strain
Make Billions of Copies.
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Steps for Making Transgenic Fish
Step 6. Isolate Plasmids from Bacteria and
Cleave into Linear Cassettes.
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Steps for Making Transgenic Fish
Step 7. Insert Over 1 Million Cassettes into
Each Newly Fertilized Egg.
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Steps for Making Transgenic Fish
Step 8. Incubate and Grow Out Surviving Fry.
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Steps for Making Transgenic Fish
Step 9. Find the Transgenics and Select Fish(s)
with Desired Characteristics.
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Steps for Making Transgenic Fish
Step 10. Breeding Program to Stabilize Transgene.
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Steps for Making Transgenic Fish

• Step 11. Seek Regulatory and Public Approval.
• Develop Food Safety Data
• Design Reliable Environmental Safety Measures
• Effectiveness Target Animal Safety Data
• Convince Regulatory Agencies (CVM and Foreign)
• Convince Producers and Customers to Buy

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Current Limitations

• Random insertion of short gene construct
• Variable numbers of copies inserted
• Insertion sites different for each individual
• Limitations
• Difficulty stabilizing genetic modification in a
  breeding population
• Uncontrolled transgene expression, zero
  withdrawal time, simple modifications only
• Insertion site effects on other genes

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Current Limitations

• Need for extensive breeding program
• Before and after modification is stabilized
• Multiple generations at 2 years each
• Data on production - fish needed for regulatory
  reviews
• Control over unlicensed, unpatented breeding
• Develop breeding biocontainment strategies

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Current Limitations

• Environmental concerns about releases
• Competition with wild populations
• Gene introgression effects on wild gene pool
• Ecological disruptions due to changes in prey
  size and other niche requirements
• Containment and biocontainment
• Engineering approaches are involved unproven
• Biocontainment research still needed

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Current Limitations

• Public International Acceptance
• Attitude differs for GM animals vs. plants
• Different attitudes for optional/premium vs.
  commodity food products food vs. drugs
• Labeling choice
• Variation among countries
• Ethical concerns stronger for animals than plants

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Current Limitations

• Competition from more widely accepted alternative
  approaches
• Genetic screening selective breeding
• Ploidy changes triploid, tetraploid, etc.
• Improved nutrition management
• Orally active growth promoters that can be
  withdrawn pre-harvest