DNA ELECTROPHORESIS

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DNA ELECTROPHORESIS
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Ladder Lanes

• DNA electrophoresis
• Migration of DNA
• DNA ladder
• Ethidium bromide

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DNA GEL ELECTROPHORESIS

• A technique in which charged particles, such as
  DNA, migrate in a gel under the influence of an
  electric field/current.
• The gel, a colloid, will act as a support for
  separation of the fragments of DNA on the basis
  of
• Size
• Shape
• Other physical properties.

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Electrophoresis system

• An electrophoresis chamber and power supply
• Gel casting tray
• Sample combs, around which molten agarose is
  poured to form sample wells in the gel.
• Buffer
• Ethidium bromide, a fluorescent dye used for
  staining nucleic acids.

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• Agar's gels
• Solidified form of agarose
• Allow DNA to move through
• dissolve dried agarose in aqueous buffer by
  heating
• Pour the warm solution into a mold which fitted
  with a well - forming comb.
• Take the comb out to form wells as the solution
  become solidified

Wells
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(-)
DNA samples are mixed with loading dye
Large DNs Small DNAs
DNA
()
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• MIGRATION OF DNA
• Size
• Shape
• Supercoiled DNAs Supercoiling winds the
  molecules up -gt smaller hydrodynamic radius
• Nicked/relaxed circular DNA have lost all of
  their superhelicity

(-)
()
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• LADDER
• A sample of DNA where the size of the DNA bands
  are known
• ETHIDIUM BROMIDE
• Included in the gel matrix to enable fluorescent
  visualization of the DNA fragments under UV
  light.
• An intercalating dye, insert itself between the
  bases stacked in the center of the DNA helix).
• Red-orange color under UV light
• A strong mutagen, may possibly be a carcinogen.

• Ladder lanes

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• Electrophoresis is usually from 0.5 1 hour,
  room temperature, depending the desired
  separation

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• GEL ELECTROPHORESIS
• Identify particular DNA molecules by band
  patterns they yield in the gel electrophoresis
  after being cut with restriction enzymes
• Isolate and purify individual DNA fragments
  containing interesting gene