Gel Electrophoresis

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Gel Electrophoresis
Developed by Science Behind Our Food University
of Georgia Adapted by Georgia Ag Ed Curriculum
Office, 2004
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What is Gel Electrophoresis?

• Electrophoresis Movement of charged particles
  through a solution (gel) under the influence of
  an electric field
• DNA fragments have a negative (-) charge and will
  move toward the positive electrode

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The Basic Components

• The gel in gel electrophoresis is the component
  that physically separates the molecules.
• The electric power supply provides the
  electricity that carries the molecules through
  the gel
• The electrophoresis chamber is where it all takes
  place.

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The Process

• Gels are often made of a gelatin-like substance
  called agarose.
• A comb with teeth is suspended in the gel until
  it cools.

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• When the gel has cooled and solidified, the
  scientist pulls the comb out of the gel.
• The teeth of the comb leave impressions in the
  gel called wells where the DNA will be loaded.

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• The gel is then placed in the electrophoresis
  chamber.
• Gel acts like a bridge through which the
  molecules must travel to get from one side of the
  chamber to the next.

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DNA PreparationRestriction Enzymes

• Cut DNA into smaller pieces
• These special enzymes recognize specific
  sequences in the DNA molecule (for example
  GATATC) and cuts the DNA wherever that sequence
  occurs.

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Loading DNA Samples into the Gel

• Gels usually contain several different samples of
  DNA for study.
• The researcher uses a pipette to draw out a
  small, precisely measured amount of each sample
  and places each sample in its own well.

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The electrophoresis After all the DNA samples
have been loaded into the wells, the electrodes
are connected to the power supply. When the
power is turned on, the negatively charged
molecules move through the gel toward the
positive pole (Remember Opposites do Attract!!).
Both the DNA fragments and the dye molecules have
a negative charge.
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http//www.life.uiuc.edu/molbio/geldigest/electro.
htmlrun
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http//www.life.uiuc.edu/molbio/geldigest/electro.
htmlrun
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Applications of Gel Electrophoresis

• DNA
• Criminal investigations
• Blood
• Saliva
• Hair
• Semen
• Paternity Tests

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Forbidden Donut Mystery

• Your Analysis Unit is charged to determine who
  took a bite of Homers Forbidden Donut.
• Posterboard ?
• Names on the Posterboard ?
• Scissors ?
• DNA strips from suspects

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Forbidden Donut Mystery

• Your Analysis Unit is charged to determine who
  took a bite of Homers Forbidden Donut.
• Posterboard GEL
• Names on the Posterboard ?
• Scissors ?
• DNA strips from suspects

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Forbidden Donut Mystery

• Your Analysis Unit is charged to determine who
  took a bite of Homers Forbidden Donut.
• Posterboard GEL
• Names on the Posterboard WELLS
• Scissors ?
• DNA strips from suspects

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Forbidden Donut Mystery

• Your Analysis Unit is charged to determine who
  took a bite of Homers Forbidden Donut.
• Posterboard GEL
• Names on the Posterboard WELLS
• Scissors RESTRICTION ENZYME
• DNA strips from suspects

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Forbidden Donut Mystery

• How to cut and place sequences on gel

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