Cloning Cloning Cloning Cloning Cloning

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Cloning Cloning Cloning Cloning Cloning
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General Questions

• What is cloning?
• How does it work?
• Can a human be cloned?
• Think of some questions.

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What is cloning?

• General term for a process of duplicating
  biological material.

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What is cloning?

• Three types of cloning
• DNA Cloning
• Reproductive Cloning
• Therapeutic Cloning

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DNA Cloning

• Its the transfer of a DNA fragment (gene) of
  interest from one organism into a
  self-replicating bacterial plasmid. The DNA of
  interest can then be placed in a foreign host
  cell. (It is basically cloning a gene or a
  chromosome)
• It has been around since the 1970s.

What is a plasmid? A plasmid is a circular piece
of DNA in bacteria that is used to copy genes and
other pieces of chromosomes to generate enough
identical material for further study.
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Reproductive Cloning
The removal of genetic material from an adult
donor cell that is placed in a host egg whose
genetic material has been removed. The host cell
is stimulated (by chemicals or electricity) to
divide. Once it reaches a suitable stage, the
cloned embryo is transferred into a uterus of a
female host until its birth.

• Dolly was created by reproductive cloning
  technology.
• a technology used to generate an animal that has
  the same DNA as another currently or
  previously existing animal.

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Reproductive Cloning

• What is the benefit?

Repopulating endangered organisms What about
dinosaurs?
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Cloning Dinosaurs

• Hard to find dino DNA.
• Dino DNA inside insects are destroyed by the
  insects digestive juices.
• Some DNA sequences have been found.
• But we dont know what the full DNA sequences
  look like, so we cant just substitute another
  organisms DNA sequence.

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Therapeutic Cloning

• - Harvesting stem cells from an embryo that can
  be used to study human development and to treat
  disease. It is not for human cloning! The embryo
  will die when the stem cells are removed.

What are stem cells? Stem cells are unspecialized
cells used to generate virtually any type of cell
in the human body and can divide many times
giving them the potential to create entire
organs. Scientists use adult stem cells and
embryonic stem cells for research.
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Kinds of Stem Cells

• Embryonic stem cells
• Derived from embryos. Specifically, embryonic
  stem cells are derived from embryos that develop
  from eggs that have been fertilized in vitro
  (outside the body).
• They are not derived from eggs fertilized in a
  woman's body.
• The embryos from which human embryonic stem cells
  are derived are typically four or five days old
  and are a hollow microscopic ball of cells called
  the blastocyst.

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Kinds of Stem Cells

• Adult Stem Cell
• An undifferentiated cell found among other cells
  in a tissue or organ that can differentiate to
  yield the major specialized cell types of the
  tissue or organ.
• The primary roles of adult stem cells in a living
  organism are to maintain and repair the tissue in
  which they are found.
• Unlike embryonic stem cells, which are defined by
  their origin (the inner cell mass of the
  blastocyst), the origin of adult stem cells in
  mature tissues is unknown.

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Adult Stem Cells

• It is believed that the stem cells lie dormant
  (non-dividing) until disease or injury triggers
  them to divide and differentiate.
• These cells, when needed, migrate to the areas
  that need them. No one knows how this occurs.

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Stem Cell Politics

• Some states are funded with money for research,
  but only on embryos that already exist.
• Laws are always changing on this issue, mostly
  because politicians dont grasp the science.

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Stem Cell Politics

• Most of the frozen embryos come from couples who
  have completed their pursuit to have children and
  dont want others to have those embryos.
• Those embryos will be destroyed unless used by
  research.

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Therapeutic Cloning

• What are the benefits?

Stem cells will be used to produce whole organs
from single cells or to produce healthy cells
that can replace damaged cells in degenerative
diseases such as Alzheimer's or Parkinson's.
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Problems with Cloning

• Expensive - 276 tries to make Dolly

Low success rates more than 90 failure
Unknown factors a more compromised immune
function and higher rates of infection, tumor
growth, and other disorders
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Should humans be cloned?

• For a number of years it will not even be an
  option, because it is so difficult. So it is not
  ethically reasonable nowbut
• What about the future?

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Ethical, Legal and Social issues

• If a clone originates from an existing person,
  who is the parent?
• Should cloning research be regulated? How, and by
  whom?
• What are some of the social challenges a cloned
  child might face?
• Is human cloning "playing with nature?" If so,
  how does that compare with other reproductive
  technologies such as in vitro fertilization?

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Murder?

• Who is responsible for the death of unused
  embryos the parents who refuse other couples to
  use the embryos or the politicians who feel it
  would be murder for using these embryos in
  research? Is it murder?

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Next Class

• Chapter 9 review
• Possible Quiz
• Test Thursday February 2