Chpt. 19:

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Chpt. 19 Genetic Engineering
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• What is genetic engineering???
• Genetic engineering is the artificial
  manipulation or alteration of genes.
• Genetic Engineering involves
• removing a gene (target gene) from one organism
• inserting target gene into DNA of another
  organism
• cut and paste process.

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Some important terms!!! Recombinant DNA the
altered DNA is called recombinant DNA (
recombines after small section of DNA inserted
into it). Genetically Modified Organism (GMO)
is the organism with the altered DNA.
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• Genetic Engineering breaks the species barrier!!!
• Genetic engineering allows DNA from different
  species to be joined together.
• This often results in combinations of DNA that
  would never be possible in nature!!! For this
  reason genetic engineering is not a natural
  process.
• If DNA is transferred from one species to
  another the organism that receives the DNA is
  said to be transgenic.

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• Genetic engineering breaks the species barrier!!!
• Examples of cross-species transfer of genes
• - a human gene inserted into a bacterium
• - a human gene inserted into another animal
• - a bacterial gene placed in a plant

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• Alternative names for genetic engineering
• Genetic Manipulation
• Genetic Modification
• Recombinant DNA Technology
• Gene Splicing
• Gene Cloning

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• Tools used in genetic engineering!!!
• Source of DNA Target (foreign) DNA DNA taken
  from one organism to be placed into the DNA of a
  second organism.
• A cloning vector Special kind of DNA that can
  accept foreign DNA and exactly reproduce itself
  and the foreign DNA e.g. Bacterial plasmid (loop
  of DNA found in bacteria).

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Tools Used in Genetic Engineering Restriction
Enzymes
- are special enzymes used to cut the DNA at
specific places. - different enzymes cut DNA at
specific base sequences known as a recognition
site. For example i) One restriction enzyme will
always cut DNA at the base sequence
GAATTC. ii) Another restriction enzyme only cuts
at the sequence GATC. - If DNA from
two different organisms is cut with the same
restriction enzyme the cut ends from both sources
will be complementary and can easily stick
together.
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• Tools used in Genetic Engineering
• DNA Ligase enzyme which acts like a glue
  sticking foreign DNA to DNA of the cloning
  vector.
• will only work if DNA from the two DNA sources
  has been cut with the same restriction enzyme
  i.e. sticky ends of cut DNA will be complementary
  to each other.
• Please note diagram illustrating use of
  restriction enzymes and DNA Ligase in production
  of recombinant DNA Fig. 19.6 pg. 195

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• Process of Genetic Engineering
• Five steps involved in this process
• Isolation
• Cutting
• Insertion (Ligation)
• Transformation
• Expression
• Note The following example will explain how a
  human gene is inserted into a bacterium so that
  the bacterium can produce human insulin.

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• Process of Genetic Engineering
• Isolation
• Removal of human DNA (containing target gene).
• Removal of plasmid (bacterial DNA) from
  bacterium.
• Cutting
• Both human DNA and plasmid DNA are cut with the
  same restriction enzyme.
• Normally plasmid has only one restriction site
  while human DNA will have many restriction sites.
• Please note diagram 19.7 pg. 196

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• Process of Genetic Engineering
• Insertion
• means that target gene is placed into the DNA of
  the plasmid or cloning vector.
• cut plasmids are mixed with human DNA sections
  allowing the cut ends to combine.
• Transformation
• Expression

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• Applications of Genetic Engineering
• You must know three applications one involving a
  plant, one animal and one for a micro-organism.
• Plants Weed killer-resistant crops
• many types of crop plants have bacterial genes
  added to them.
• these genes make the plants resistant to certain
  weed killers (herbicides).
• this means that the weed killers kill the weeds
  but do not affect the transgenic plants.

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Applications of Genetic Engineering Animals
There is a growing trend to experiment with
inserting human genes into the DNA of other
mammals. The transgenic animals formed in this
way will then produce a human protein and secrete
it into their milk or even into their eggs.
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• Applications of Genetic Engineering
• Animals Sheep produce human clotting factor
• A human gene has been inserted into the DNA of
  sheep.
• This allows the adult sheep to produce a
  clotting chemical needed by haemophiliacs to clot
  their blood produced in the milk of the sheep.
• Pharming is the production of pharmaceuticals by
  genetically modified animals i.e. sheep, cows,
  goats etc.

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Pharming using animals to make pharmaceuticals
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• Applications of Genetic Engineering
• Micro-organisms Bacteria make insulin
• The human insulin gene has been inserted into a
  bacterium (E-coli).
• This allows the bacterium to produce insulin for
  use by diabetics.

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• Ethical Issues in genetic engineering
• The release of GMOs into the environment
• Danger of possibility of GMOs being released
  into the environment.
• GMOs grown in bioreactors do not provoke as
  much fear.
• GMOs grown outdoors - fears of foreign genes
  they contain being spread to other plants.

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• Ethical Issues in Genetic Engineering
• GMOs as a food source
• Outlined below are some fears associated with the
  use of GMOs as a food source
• Cannibalism
• eating an animal containing a human gene is a
  form of cannibalism.
• - feeding GMOs containing human genes to
  animals that would later be eaten by humans.
• Religious reasons eating pig genes that are
  inserted into sheep would be offensive to Jews
  and Muslims.
• Offensive to vegetarians/vegans eating animal
  genes contained in food plants cause concern.

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• Ethical Issues in Genetic Engineering
• Animal Welfare
• There is serious concern that animals will
  suffer as a result of being genetically modified.
• use of growth hormones may cause limb
  deformation and arthritis as animals grow.

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• Ethical Issues in Genetic Engineering
• Genetic Engineering in Humans
• The following issues are a cause for concern
• If tests are carried out for genetic diseases,
  who is entitled to see the results?
• Tests on unborn babies could this lead to
  abortion if a disease is shown to be present?
• Insurance/lending companies will they insist
  on genetic tests before they will insure/lend
  money to a person?
• Need for legal controls over the uses to which
  human cells can be put.
• Development and expansion of eugenics.