Chapter 9 Tortora

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Chapter 9 Tortora

• Biotechnology and Recombinant DNA

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Recombinant DNA Technology

• http//www.bioteach.ubc.ca/TeachingResources/Appli
  cations/GMOpkgJKloseGLampard2.swf GO here for a
  brief animation
• Genes are inserted into cells using recombinant
  DNA technology.
• A gene from a vertebrate (human) can be inserted
  into DNA from a bacterium
• The recipient then expresses the gene (makes the
  protein) which may be commercially useful
  (insulin)

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How does this work?

• Vector (plasmid) is isolated
• DNA is cleaved by an enzyme into small pieces
• Gene of interest is inserted into vector DNA in
  vitro
• rDNA is taken up by cell (bacterium) and
  multiplies
• These are grown in culture to form clones
• Researcher harvests large quantities of the gene
  of interest for other uses OR
• If the gene is expressed in the cell clone its
  protein is harvested and used

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Already in use

• Human growth hormone
• Human insulin
• Vaccine for hepatitis B
• Interferon

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Tools of Biotechnology

• Biotechnology is the use of microbes, cells, or
  cell components to make a product
• 1. selection-select bacteria that show desirable
  traits
• 2. mutation-site directed mutagenesis can make
  specific changes in a specific gene to enhance a
  desired trait

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3. Restriction enzymes

• Special DNA cutting enzymes that exist in many
  bacteria
• Isolated in 1970
• These cut or digest only certain sequences of DNA
  nucleotide bases
• Recognize 4, 6, or 8 base sequences
• Make staggered cuts leaving sticky ends

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

• Sticky ends can be join by attaching
  complementary base pairs (and hydrogen bonding)
  to form a linear chain or a circular one.
• DNA ligase links the pieces like glue and
  produces the rDNA molecule

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Scientific applications

• Sequencing of the human genome
• Created the field of bioinformatics which uses
  computer analysis to understand the function of
  genes
• This is used to compare patterns and try to
  identify virulence factors in microorganisms
• Identify and clone the gene that causes CF
  (cystic fibrosis) that has lead to genetic
  screening of hundreds of genetic diseases

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More applications

• Forensic microbiology-DNA fingerprinting to
  identify pathogens
• Agricultural applications-creating genetically
  desirable plants
• Look at table 9.1 to see some of the
  pharmaceutical products of genetic engineering