Transcript Cloning Powerpoint

Cloning
3 Types of Cloning
• Transgenic (gene) cloning
• Therapeutic (stem cell) cloning
• Reproductive (organism) cloning)
Transgenic
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Organisms that contain another species’
genes within their chromosomes
First transgenic organisms were bacteria
Scientists around the world use
customized transgenic animals for their
own research
Transgenic
Benefits of transgenic animals
– Animal models
– Pharmaceutical production
– Organ donors
– Livestock improvement
Production of transgenic animals
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The transgene (which contains the DNA
the scientist wants to transfer) is
introduced into a single-cell embryo
The embryo is transferred to a surrogate
mother of the same strain
Success rate is low (10%-30%) in mice
Success rate decreases in mammals
Transgenic
Care of transgenic animals
– Most do not require special care
– Some develop a susceptibility to disease
Government’s view
– May patent new organisms
– Regulated by NIH
Future of transgenic animals
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Current research limited to transferring a
small amount of genes at a time
Much work remains to be done to finetune techniques
Possible effects of foreign DNA remains
a concern
The use of transgenic models is an
established part of biomedical research
Therapeutic Cloning
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Procedure used to produce embryonic
stem cells that theoretically can be used
to treat diseases
Goal of therapeutic cloning is to produce
embryonic stem cells
In therapeutic cloning, the embryo is not
placed in a surrogate, but rather,
undergoes cell division in the lab until it
reaches blastocyst stage.
Therapeutic cloning
• Types of Stem cells
– Embryonic
– Adult
– Amniotic
Human stem cell research
– 2001 legislation allowed federal funding of
research using 64 existing human
embryonic stem cells
– Same legislation declared no federal funds
for additional research.
– Researchers must use existing human stem
cell lines for research or find private funding
sources
Therapeutic Cloning
Therapeutic
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Creation of embryonic
stem cells does not
always use fertilized
egg
On the other hand, it
does have the potential
to become a living thing
if transplanted into the
uterus
Question – is life
destroyed if the stem
cells are removed from
the blastocyst four days
later?
Therapeutic
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Real advantage of stem cells –
permits the production of
perfect-match tissue
Scientists have found that
embryonic stem cells pick up
cues from neighboring cells and
differentiate into that cell type
Scientists hope stem cells will
be used to treat heart disease,
Parkinson’s disease, other
disorders of the nervous
system
Reproductive Cloning
Reproductive Cloning
– Goal of reproductive cloning is to create a
new organism, human or animal
– Clone = precise genetic copy
– Reproductive cloning is really somatic cell
nuclear transfer (SCNT)
– Dolly the sheep – first cloned mammal in
1997
– Very few scientists believe human cloning
(reproductive cloning) should be permitted
Reproductive cloning
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Obstacles to reproductive cloning using
animals
– Success rate very low
– Vast majority of problems occur during fetal
development
– Additional problems show up after birth and
years later
– “Large offspring syndrome” = cloned
newborns 20-30% larger than usual, making
it hard to deliver unborn babies