DNA Technology and Genomics

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DNA Technology and Genomics

• Chapter 20
• Biology Campbell Reece

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Gene Cloning

• Method for producing multiple identical copies of
  gene-sized pieces of DNA
• Can be used for basic research of in commercial
  applications
• Human growth hormone, insulin
• Proteins that dissolve blood clots
• Bacteria for cleaning up toxic waste
• Pest resistance in plants

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Gene Cloning
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Restriction Enzymes

• Enzymes that cut DNA molecules at a limited
  number of specific locations
• Recognize short nucleotide sequences
• The restriction fragments are double-stranded DNA
  fragments with at least one single-stranded end,
  called a sticky end
• These sticky ends are where the new DNA will be
  inserted and attached using DNA ligase

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Restriction Enzymes

• The resulting DNA is known as recombinant DNA
• Bacterial plasmids are commonly used in this
  process as cloning vectors

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Cloning a Eukaryotic Gene

• Isolate the vector (plasmid) DNA and the gene of
  interest
• Insert the DNA into the vector
• Introduce the vector into cells
• Clone the cells (and therefore the foreign gene)
• Identify the cell clones that carry the gene of
  interest

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Cloning a Eukaryotic Gene
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Polymerase Chain Reaction (PCR)

• A technique by which any piece of DNA can be
  quickly amplified (copied many times) without
  using cells
• DNA is incubated in a test tube with a special
  kind of DNA polymerase, a supply of nucleotides,
  and short pieces of single-stranded DNA that
  serve as primers
• PCR can make billions of copies of a targeted
  segment of DNA in a few hours

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PCR
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Gel Electrophoresis

• Separates macromolecules on the basis of size,
  electrical charge other physical properties
• Separates DNA molecules into bands of molecules
  of the same length

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DNA Fingerprinting