Transcript Cloning - Sintich Science

What is it?
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Mammal cloning is the process of taking somatic
cells from a donor (cannot be nerve cells from
CNS or red blood cells because they do not
continually divide) and stripping it of its nucleus. It
is the placed into an egg cell to be developed
within a surrogate mother.
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In order for this happen, the cells must be
exposed to the least amount of mutagens
possible.
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There are currently three methods to animal cloning.
1. Splitting off a cell from an embryo (twinning): An egg is fertilized
normally and divides. Some cells are then taking and placed in a
different mother.
2. The Roslin technique: This technique consists of a donor cell and
an oocyte. The nucleus is removed from the egg cell and replaced
with the nucleus from the donor cell (cell fusion, transplantation).
The embryo is transplanted into mothers.
3. The Honolulu technique: This process uses adult cells and nuclei.
After the nucleus is transferred from the donor cell to the egg, the
cell is jumpstarted (through chemical culturing) to create embryos
that are placed into surrogate mothers for development.
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Clones are genetically
identical copies with the
same genetic information.
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Although they have the
same genotype, they may
not necessarily have the
same phenotype due to
environmental conditions
(nature vs. nurture).
Where does it originate?
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Cloning of plants has been a very common
practice for hundreds of years.
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Small animal cloning has dated back to the
1960s.
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After the cloning of Dolly (the sheep- discussed
later), many larger animals have been cloned.
The idea of the possibility of human cloning has
also been debated.
How has it been used?
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1996: Scottish
researchers produced
Dolly (from an utter cell
of 6 year old sheep).
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1998: Japanese
researchers attempted
to clone eight calves
from one cow. Only four
survived.
How is it helpful?
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Cloning can be used to produce animals for medical research
purposes.
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Although human cloning is not yet available due to ethical
concerns, some researchers say it can be used to help sterile
couples have children.
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It can be used to create genetically identical animals that
have a specific desired gene or phenotype (such as healthy
milk-producing cows). The Dolly researchers were able to
clone genetically modified sheep to produce better milk
containing human proteins that are essential for blooding
clotting.
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2008: FDA approved that all products coming from cloned
animals are safe for consumption.
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Cloning can also be used to test new drugs because identical
organisms can produce identical reactions. This helps
researchers to understand the actual effects of the drug.
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Researchers are also focusing on the prevention of extinction
or endangered species through cloning. Questions have arose
regarding the restoration of the woolly mammoth through tissue
that has remained alive in the laboratory.
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Some may even chose to clone their deceased pets (as in the
case with CC the cat.
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Researchers are also
attempting to use
therapeutic cloning: an
embryo is cloned from
stem cells with the same
DNA as the donor cell.
This can help with
understanding and the
prevention of certain
diseases.
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With human cloning, researchers could be rid of
defective genes (cloning of healthy human cells).
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Traumatic injuries can be healed faster through
cloning of that person's cells.
What are the potential
problems?
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Most cloned animals do not survive. Dolly was the
only one out of 227 cloned embryos to survive.
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Often times, there is an increase in birth size and
faster aging.
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There are concerns with organ defects.
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Premature aging and immune system problems
can also occur.
What are the ethical
considerations?
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With therapeutic cloning, there are issues and concerns related to
the destruction of cloned embryos. Stem cells are gathered at
blastocyst stage of development (first five days after development)
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Cloning may also reduce genetic variation in animals.
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There are some concerns with creating genetically identical people
that go against religious or societal values.
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Most religions agree that life can only begin at conception, and can
be formed only by the uniting of a male and female. Some religions
view humans as being created by God, so people,do. It have the
right to attempt to create a human being.
References
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http://www.humancloning.org/threeways.htm
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http://www.biology.iupui.edu/biocourses/N100/2k4cloningnotes.html
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http://brookscole.cengage.com/chemistry_d/templates/student_resources/0030244269_campbell/Hot
Topics/MammalianCloning.html
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http://redicecreations.com/article.php?id=13862
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http://learn.genetics.utah.edu/content/cloning/whyclone/
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http://science.howstuffworks.com/life/genetic/cloning3.htm
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http://www.slideshare.net/14boggas/honolulu-cloning-technique
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http://www.bioarts.com/team_ji.htm
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http://www.genome.gov/25020028
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http://healthresearchfunding.org/pros-cons-human-cloning/
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http://bsp.med.harvard.edu/?q=node/18