Hypothetical Situation

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Hypothetical Situation

• Genes that produce chlorophyll in plants are
  inserted into the chromosomes of cattle.
• What are some of the advantages of this
  procedure?
• The result would be an animal that is capable of
  making its own food.
• Can you think of the potential benefits of this
  kind of research?

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DNA Recombination

• a.k.a. Gene Splicing

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What is it?

• Recombinant DNA refers to a new combination of
  DNA molecules that are not found together
  naturally.
• Produced by joining DNA molecules from different
  biological sources.
• The hybrid DNA is then inserted into a host cell,
  often a bacterium, for replication.

Click
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Tools Needed

• Restriction enzymes (biological scissors) "cut"
  DNA at a specific location.
• DNA ligase (DNA glue) is used to "glue" two
  sections of DNA together.

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Plasmids

• Recombinant DNA is often created using a plasmid.
• Plasmids are DNA structures in bacteria

http//faculty.abe.ufl.edu/chyn/age2062/lect/lect
_09/FG10_001.GIF
http//www.microbeworld.org/microbes/virus_bacteri
um.aspx
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or Viruses

• The DNA in a virus can also be used for creating
  recombinant DNA
• The virus can enter another cell and have its
  genetic code replicated by that cell

http//www.microbeworld.org/microbes/virus_bacteri
um.aspx
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Products of Recombinant DNA Technology

• Some examples of recombinant DNA products include
  insulin and growth hormone.
• Vaccines can also be produced using recombinant
  DNA technology.

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Step by Step

• Lets look at the process of DNA recombination

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Step 1 A restriction enzyme is used to cut a
specific DNA strand from the DNA of a cell
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Step 2 The cut DNA strand is inserted into a
virus.
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Step 3 The virus is inserted into a cell
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Step 4 The cell passes the foreign gene on to
all daughter cells
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• A Close-up View of DNA insertion into a plasmid

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Areas Where Recombinant DNA will have an Impact

• Better Crops (drought heat resistance)
• Recombinant Vaccines (ie. Hepatitis B)
• Prevention and cure of sickle cell anemia
• Prevention and cure of cystic fibrosis
• Production of clotting factors
• Production of insulin
• Plants that produce their own insecticides
• Gene therapy

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Connections to the World Around Us
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Activity

• Make your own recombinant DNA!!

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Impact of Recombinant DNA

• Improved Medicines
• Improved Livestock (resistance to disease)
• Improved Crops (resistance to disease, higher
  yields)
• Prevention of Genetic Diseases
• Lowering the cost of medicines (i.e. Insulin)
• Safer Medicines (i.e. Insulin)
• Treatment for pre-existing conditions (i.e.
  Cancer)

• Safety concerns (viruses developing antibiotic
  resistance)
• Environmental concerns (developing resistance to
  fungi)
• Ethical dilemmas over human treatment (i.e. are
  we playing God?)
• Potential for Experimental abuse (doctors using
  patients as test subjects)
• Germline treatment going from treating diseases
  to a method for picking the traits you want in a
  child (i.e. specifying hair and eye color)

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Cutting DNA Strands
The major tools of recombinant DNA technology are
bacterial enzymes called restriction enzymes.
Each enzyme recognizes a short, specific
nucleotide sequence in DNA molecules, and cuts
the backbones of the molecules at that sequence.
The result is a set of double-stranded DNA
fragments with single-stranded ends, called
"sticky ends." Sticky ends are not really sticky
however, the bases on the sticky ends form base
pairs with the complementary bases on other DNA
molecules. Thus, the sticky ends of DNA fragments
can be used to join DNA pieces originating from
different sources.                              
                          
http//www.accessexcellence.org/RC/AB/WYW/wkbooks/
SFTS/activity6.html
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Creating Recombinant Plasmids

• In order to be useful, the recombinant DNA
  molecules have to be made to replicate and
  function genetically within a cell. One method
  for doing this is to use plasmid DNA from
  bacteria. Small DNA fragments can be inserted
  into the plasmids, which are then introduced into
  bacterial cells. As the bacteria reproduce, so do
  the recombinant plasmids. The result is a
  bacterial colony in which the foreign gene has
  been cloned.

http//www.accessexcellence.org/RC/AB/WYW/wkbooks/
SFTS/activity6.html