Hardin Rahe, Ph'D' Professor and Chair Department of Agriculture

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Hardin Rahe, Ph.D.Professor and ChairDepartment
of Agriculture
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What are clones?

• Two or more organisms with identical genetic
  make-up derived by ASEXUAL REPRODUCTION from a
  single common parent or ancestor. This definition
  has, as a result of recent advances in cloning
  techniques, been extended to include organisms
  that are a genetic copy or replica of one another.

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The Technology of Cloning

• Cloning requires specialized microsurgery tools
  and involves five basic steps
• Enucleation of the recipient egg
• Transfer of the donor cell into the recipient egg
  
• Fusion of the donor cell to the recipient egg
• Culturing the resulting cloned embryo in the
  incubator
• Transferring the developing embryo into the
  reproductive tract of a surrogate mother

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The Micromanipulator Station

• A compound microscope with a left and right hand
  micromanipulator is required in the cloning
  procedure.
• The microscope magnifies the specimen and the
  micromanipulators reduce the technician's hand
  movement to allow microsurgery.

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The Micromanipulator Station (Close-up)

• The tool on the left, called the holding pipette,
  is used to hold the egg.
• The tool on the right, called the enucleation
  pipette, is used to remove the genetic material
  from the egg and then used to place the donor
  cell adjacent to the egg membrane.

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Step 1 - Enucleation of the Recipient Egg

• The egg is typically matured for about 24 hours
  so that the genetic material (DNA) is congregated
  in the nucleus.
• The enucleation pipette is then used to pierce
  the egg shell and penetrate the egg membrane.
• Suction is applied and the nucleus containing the
  genetic material is removed and discarded.

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Obtaining the Donor's Genetic Code

• Following the removal of the nucleus from the
  recipient egg, a single donor animal skin cell is
  removed from the growing colony.
• This is done by creating a suction on the
  enucleation pipette.

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Step 2 - Transfer of the Donor Cell Into the
Recipient Egg

• Still using the micromanipulator, the donor skin
  cell is then placed adjacent to the enucleated
  egg membrane in the perivitelline space (between
  the egg shell and the egg membrane).
• The membrane of the donor cell and the membrane
  of the recipient egg must be touching for fusion
  to occur.

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Cell Fusion Equipment

• A BTXTM cell fusion machine is used to fuse the
  donor cell with the enucleated egg.
• Electric leads from the BTXTM machine are
  connected to a special fusion chamber that is
  placed on the stage of a microscope so that the
  technician can properly position the donor cell
  and enucleated egg.

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Step 3 - Fusion of the Donor Cell to the
Recipient Egg

• The egg and the donor cell are placed in the
  fusion chamber between 2 electrodes.
• When the 2 membranes fuse together, the nucleus
  (containing all the genetic material from the
  donor animal) of the skin cell is now surrounded
  by the recipient egg.

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Step 4- Culturing the Resulting Cloned Embryo in
the Incubator

• This embryo is cultured in the incubator and it
  begins cell division in a manner similar to that
  of a conventionally fertilized egg.
• It will divide into 2-cells, 4-cells, 8-cells,
  etcetera.
• The incubation period lasts roughly 3 to 5 days.

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Cloned Goat Embryos

• These five cloned goat embryos at the 8 to 16
  cell stage are nearing the time for transfer into
  the surrogate mother's reproductive tract

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Step 5 - Transferring the Developing Embryo Into
the Reproductive Tract Of A Surrogate Mother

• The cloned embryos are transferred into the
  reproductive tract of a synchronized surrogate
  female of the same species.
• Depending on the species of the clone, the
  embryo is transferred at the 8 to 64 cell stage.
• The surrogate mother will carry the clone to term
  and give birth as in a normal pregnancy.

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Babies

• The offspring that result from this procedure are
  genetically identical to the donor animal that
  the skin biopsy was taken from.
• They are genetically identical to each other and
  to their donor "parent".

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Why clone?

• 1. Medical purposes
• ? Cloning animal models of disease
• ? Cloning stem cells for research
• ? "Pharming" for drug production
• 2. Agricultural purposes
• ? Ugrade herd quality
• ? Increase disease resistance
• ? Enhance animal efficiency
• 3. Revive endangered or extinct species
• 4. Reproduces a deceased pet
• 5. Cloning humans?

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Questions?

• Is cloning "unnatural"?
• Is an identical twin essentially the same as a
  clone?
• Could someone clone Hitler if human cloning were
  perfected?
• 4. Could clones be "farmed" to provide spare body
  parts for their "parent" clone without problems
  of tissue rejection?
• 5. Would a clone have a soul?
• 6. Could people be cloned without conscious
  brains (so their body parts could be harvested
  with fewer moral qualms)?
• Could vital organs be grown using cloning without
  the rest of a body?
• Could cloning be used to save endangered species?