Cloning: Dolly and beyond

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Cloning Dolly and beyond

• Cloning is a type of asexual reproduction
  performed in a laboratory that produces identical
  individuals from a cell or from a cluster of
  cells taken from a multicellular organism.

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What was Dolly?

• In 1997 Dolly the sheep became the first
  vertebrate cloned from the cell of an adult
  animal. Not only was this a remarkable
  scientific breakthrough but it immediately gained
  interest and concern from around the world on the
  future of cloning technology as it would effect
  humans.

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Topics of Discussion

• What is cloning?
• Methods of cloning
• Dolly in detail
• Dollys probability
• Todays legality
• The future of cloning
• Ethical final questions

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What is cloning?

• Reproductive cloning- The entire animal is
  produced from a single cell by asexual
  reproduction. This would allow for the creation
  of a human being who is genetically identical to
  another.
• Therapeutic cloning- Broader use of the term
  cloning. Does not create a new genetically
  identical individual. Research includes therapy
  for human mitochondria disease and others that
  could replace damaged or diseased tissues without
  the risk of rejecting anothers tissue. Could
  create new skin tissue for burn patients.

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Other types of cloning

• Multiple copies of genes or gene fragments,
  repeating nucleotide sequences
• Single cell organisms, like bacteria and fungi.
  This includes fermentation processes for
  production of bread, beer, and wine.
• Entire plant asexual replication
• Natural cloning occurs in sexual reproduction,
  when the embryo splits in two to produce twins.

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Plant Cloning

• Culture a tissue culture enables planet growers
  and scientist to make many copies of a plant with
  desirable traits.
• Tissue culture also enables plant growers to
  reproduce plants that might have become infected
  with disease
• A plant becomes infected with a disease, can be
  cloned using meristern (non-infected) cells.

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Methods of cloning

• Embryo splitting- Artificially splitting a
  single embryo at a very early stage of
  development. In the natural process this would
  create twins. However, because this is done at an
  early stage and there are usually less than eight
  cells you can only make a few clones. Both the
  nuclear genes and mitochondria genes would be
  identical.

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Methods of cloning

• Nuclear replacement- Genetic material (nucleus
  from embryonic, fetal, or adult cell) is removed
  and placed into an unfertilized egg or embryo,
  whose nucleus has been removed. In this case the
  nuclear genes remain the same but the
  mitochondria DNA would be different. This has
  the potential to create the clone of an adult
  organism as well as many clones at once.

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Dolly in detail

• Dolly was cloned using the nuclear replacement
  method. Again the nucleus with chromosome sets
  is fused with an unfertilized egg whose nucleus
  has been removed.
• Motivating factor was that it could help to
  improve certain qualities in livestock.
• Dolly was not the first sheep to be created from
  nuclear replacement. Two genetically identical
  sheep, Megan and Morag were born in 1996 using
  the technique. The difference was that Dolly was
  derived from an adult sheep, and Megan and Morag
  were from a sheep embryo.

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Dollys probability

• Cells taken from a six-year-old Finnish Dorset
  ewe and cultured in a lab.
• 277 cells then fused with 277 unfertilized eggs
  (each with the nucleus removed)
• 29 viable reconstructed eggs survived and were
  implanted in surrogate Blackface ewes.
• 1 gave birth to Dolly
• 0.361 chance at onset, 3.4482 once implanted.
  In nature between 33-50 of fertilized eggs
  develop.

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Todays Legality

• In Great Britain, clones are allowed to be made
  and born. Cloning does require a license, and
  scientists must follow strict guidelines.
• 1990 Human Fertilization and Embryology Act
  allows research on embryos for up to fourteen
  days.
• Most laws state that any embryo that has been
  researched upon cannot be then placed into a
  uterus.

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Todays Legality

• 1997 House bill prohibited use of federal money
  for experimentation with cell transfer technology
  to produce an embryo that is a human clone.
  Federal rules prohibit federal funding for embryo
  research. The bill allowed for continuation of
  federal research on plant and animal cloning. It
  did not affect research at biotech companies or
  academic institutions, which don't receive
  federal funding.

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The future of cloning

• Research could give insight to origins of cancer
  and other cellular processes such as aging.
• Techniques could be used with nerve cells that do
  not regularly reproduce. Could possibly help
  Alzheimer or Parkinsons sufferers.
• Nuclear replacement could help those with
  diseases that are inherited from mitochondria.
  The nucleus is removed from the diseased cell and
  placed into one with healthy mitochondria.

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Ethical final questions

• Are human clones individuals?
• Do clones have parents? Who are they? The cell
  donor? Nucleus donor? Surrogate?
• How old is a clone? Go by age of DNA or age of
  tissues?
• Do the benefits of cloning outweigh possible
  number of trials (possibly failed ones) that
  would have to occur with human embryos?
• Is it ok to clone for outstanding individuals
  physically or mentally? For experiments?