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DNA Technology

• Recombinant DNA and Genetic Engineering

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Outline

• 1. Key Concepts
• 2. DNA Cloning
• 3. Genetic Engineering
• 4. Key Terms
• 5. Conclusions

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Key Concepts

• Genetic experiments have been proceeding in
  nature for billions of years
• Genetic changes are brought about by Recombinant
  DNA technology
• With technology, researchers can isolate, cut,
  and splice together gene regions from different
  species, and amplify the number of copies

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Key Concepts

• Recombinant DNA technology depends on 3
  activities
• Cutting DNA into fragments
• Insertion of fragments into cloning tools like
  plasmids
• clone and identification of desired clone
• Genetic engineering involves isolating,
  modifying, and inserting genes back into the same
  organism or into a different one
• Social, ethical, legal, and ecological questions
  are raised by the new technology

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Glowing mice
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Producing Restriction Fragments

• Restriction enzymes
• Cut at specific nucleotide sequences
• Some create Sticky Ends
• DNA fragments cut with the same restriction
  enzyme will base-pair to form recombinant
  fragments
• DNA ligase
• Seals nicks where fragments base pair

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Using a restriction enzyme and DNA ligase to make
recombinant DNA
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DNA Cloning and Genome (DNA) library
e. DNA fragments and modification enzymes are
mixed together
a. Restriction enzyme cuts chromosomal or cDNA
c. DNA or cDNA fragments
f. A collection of recombinant plasmids
d. Plasmid fragments
b. Same enzyme cuts plasmid DNA
g. Host cells able to divide rapidly take up
recombinant plasmids
The original plasmid is called a cloning vector
(taxi for delivering foreign DNA into a
bacterium)
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Human gene Cloning
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Complementary DNA (cDNA)

• Reverse transcription
• cDNA library

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Polymerase Chain Reaction (PCR)(any piece of DNA
can be quickly amplified)

• Heat DNA to unwind to single strands
• Add primers that base-pair with ends
• Cool mixture to promote base-pairing
• DNA polymerase assembles complementary sequences,
  doubling number of identical fragments
• Repeat process over and over

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Genetic engineering

• The goal is to beneficially modifying traits that
  the genes influence.

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Bacteria

• Genetically Engineered Bacteria
• Insulin production
• Growth hormone
• Oil degraders
• Pesticide control

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Plant
Genetically engineered cotton plant having a gene
for herbicide resistance. Both had been sprayed
with a weedkiller
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Regenerating Plants from Cultured Cells
Plant glows in the dark owing to a gene transfer
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Genetic Engineering of Animals

• Insertion of gene into fertilized egg
• Animals produce new products
• Cloning
• Dolly

Dolly and her first lamb
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Applying the New Technology to Humans

• Human Genome Project
• 3.2 billion base pairs
• 99.9 of nucleotide sequence is same for all
  humans
• 0.1 account for all genetic differences

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DNA Sequencing
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Key Terms
Genomic library Polymerase chain reaction Human
Genome Project
Genetic engineering Recombination
DNA Biotechnology Gene cloning Restriction
enzymes cDNA Cloning vector Stick ends DNA
ligase PCR
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In Conclusion

• Nature conducts her own genetic engineering
  experiments
• Recombinant DNA technology allows the isolation,
  cutting, and splicing of gene regions
• Restriction enzymes and DNA ligase allow new DNA
  to be inserted into plasmids
• DNA libraries are collections of DNA fragments
• Amplification can be done using bacteria or yeast
  or by PCR

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In Conclusion

• Genetic engineering involves the isolation,
  modification, and insertion of genes
• Recombinant DNA technology and genetic
  engineering have potential research and
  applications in medicine, agriculture, and
  industry