Transcript How Dolly was created

Biology Project
Animal Cloning
Content
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1.Introduction
2.Technology and Processing
3.Triggered Problems
4.PROs and CONs
5.Prospects
6.Conclusion
Introduction
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Cloning of a more limited sort has been done for years researchers have already cloned mice, frogs, and sheep with
cells taken from embryos. The success of cloning Dolly, the 1st
mammal to be cloned from a mature ewe, makes a stunning
breakthrough. Since then, this reality of animal cloning stares us
in the face and human cloning around the corner. Proponents of
human cloning assists that this technology can lead medical
science into a new epoch. However, many problems are also
raised, such as moral and ethical arguments. Some protests
afraid that cloning of human may damage the human species as
well.
How Dolly was created
Nuclear Transfer Technology
• 1.Nuclear transfer involves transferring the complete genetic material (the DNA
contained in a nucleus) from one cell into an unfertilised egg cell whose own nucleus
has been removed.
• 2.A technique known as twinning exists, but can only be used before an organism’s
cells differentiate. All cloning experiments of adults mammals have used a variation of
nuclear transfer.
• 3.Nuclear transfer requires two cells, a donor cell and an oocyte, or egg cell.First, the
donor cells are grown under special conditions in culture. In this way the number of
cells can be increased by several orders of magnitude. It is also possible to make genetic
modifications and to select just those cells in which the desired modification has
occurred and multiply these up.
• 4.Research has proven that the egg cell works best if it is unfertilized, because it is
more likely to accept the donor nuclear as its own. The egg cell must be enucleated. This
eliminates the majority of its genetic information.
• 5.The donor cell is then forced into the Gap Zero, or GO cell stage, a dormant
phase, different ways depending on the technique. This dormant phase causes
the cell to shut down but not die. In this state, the nucleus is ready to be
accepted by the egg cell.
• 6.The donor cell’s nucleus is then placed inside the egg cell, either through
cell fusion or transplantion. The egg cell is then prompted to begin forming an
embryo. When this happens, the embryo is then transplanted into a surrogate
mother. If all is done correctly, occasionally a perfect replica of the donor
animal will be born naturally.
• Method of Nuclear Transfer in Livestock
Remarks of Nuclear transfer
Technology
• 1. This technology could allow the production of genetically identical groups
of animals which possess a desirable genetic trait.
• 2. The work to date has shown the technology to be successful only in sheep.
• 3. PPL Therapeutics hopes to use this technique to enable the production of
new drugs for the treatment of a range of conditions using its transgenic
technology. This could lead to cheaper drugs for currently untreatable diseases.
Triggered Problems
• Cloning may trigger some problems:
• In fact,the adult female ewe is both the genetic mother and the genetic
father of Dolly.And the female from whom the egg came and the
female who gestated Dolly and gave birth to her are two more maternal
to her.Which of these we would even call the parent to Dolly?Also,if
you’re cloning someone to replace a child who died,then you might
love the new child especially dearly.But the new child might not
particularly like the fact that was the reason it was born.
• Creating animals with genetic defects also
raises challenging ethical questions
• Cloning would further violate human dignity by denying the intrinsic
value of each human life,thereby viewing human being as commodities
oppose surrogate parenting contracts,genetic screening of embryos
before uterine implanting and sex selection abortion.Because a cloned
person will not be created simply for their value as a person.
PROs
• It seems clear that cloning from cultured cells will offer important
medical opportunities.For example,to help to produce discoveries that
will effect the study of genetics, cell development, human growth, and
obstetrics.The advantages of cloning animals are displayed here.
• 1.Producing a greater understanding of the cause of
miscarriages
• Cloning may lead to a treatment to prevent spontaneous abortions-help
women who can't bring a fetus to term. Also, It might lead to an
understanding of the way a morula (mass of cells developed from a
blastula) attaches itself to the uterine wall. This might generate new
and successful contraceptives.
• 2.Generation of genetically modified animal organs
• Cloning can generate genetically modified animal organs that are
suitable for transplantation into humans.At present,thousands of
patients die every year before a replacement heart,liver or kidney
becomes available.A normal pig organ would be rapidly destroyed by a
“hyperacute” immune reaction if transplanted into a human.This
reaction is triggered by proteins on the pig cell that have been modified
by an enzyme.
• 3. Preventing child suffering heredity
• Cloning could also be used for parents who risk passing a defect to a
child. A fertilized ovum could be cloned, and the duplicate tested for
disease and disorder.This could help the child to prevent suffering
heredity.
• 4.Cure damaged nervous system
• Damage to the nervous system could be treated through cloning.
Damaged adult nerve tissue does not regenerate on its own. However,
stem cells might be able to repair the damaged tissue.Human can help
to produce large number of cells.
CONs
• To those against it,cloning presents as much a moral problem as a
technical problem.Cloning is an affront to religious sensibilities,and
interfering with the natural process. There are objections, regarding
susceptibility to decrease,expense,and diversity.Their basic disadvantages
to cloning research are as follows:
• 1.Reducing genetic variability
• Producing many clones runs the risk of creating a population that is
entirely the same, susceptible to the same diseases, and one disease could
devastate the entire population.There are more probable events could
occur from a lack of genetic diversity.
• 2.Interfering with natural evolution
• Cloning may cause people to settle for the best existing animals, not
allowing for improvement of the species. In this way, cloning could
potentially interfere with natural evolution.
• 3.Risk of disease transfer
• Risk of disease transfer between transgenic animals and the animal
from which the transgenes were derived.e.g. If an animal producing
drugs in its milk becomes infected by a virus, the animal may transmit
the virus to a patient using the drug.
• 4.Genetic tailoring of offspring
• The ability to clone humans may lead to the genetic tailoring of
offspring. It is conceivable that scientists could alter a baby's genetic
code to give the individual a certain color of eyes or genetic resistance
to certain diseases. This is viewed as inappropriate tampering with
"Mother Nature" by many ethicists.
• 5.Detrimental effect on familial relationships
• A child born from an adult DNA cloning of his father could be
considered a delayed identical twin of one of his parents. It is unknown
as to how a human might react if he or she knew he or she was an
exact duplicate of an older individual.
The future of Cloning
• 1.Contributing the biomedical and pharmaceutics.
• Through nuclear transfer,bio medical research and pharmaceutics,
medicine and hormones can be produced. If human genes are
introduced into other organisms, like pigs and sheep, these transgenic
animals can produce human proteins. Animals can be used as "drug
factories," producing human proteins and producing insulin,used to
treat diabetes.Transgenic sheep can produce a drug that is used to treat
cystic fibrosis.
• 2.Contributing to disease treatment
• Cloning research may contribute to disease treatment,for example,skin
cells could be reprogrammed into the insulin producing cells
in the pancreas. These skin cells would then be introduced into the
pancreas of a diabetes patient, allowing them to produce insulin.
Parkinson's Disease is a degenerative disease affecting neurons.
Cloning research could allow the reprogramming of cells into neurons
to replace those damaged by Parkinson's.
• 3.Contributing to organ transplantation
• Through cloning, organ transplantation may become a more successful
process. Although organ transplantation is a common occurrence, there
is often a shortage of organs suitable for transplantation.
Xenotransplantation, transplanting organs from one species to another,
provides a solution to organ shortage. From future cloning research,
human organs may be cultured from outside the body. In the future,
humans might be able to clone their own organs for personal
transplantation.
• 4.Contributing to create a clone from the dead to
duplicate extinct animals
• If they’ve been frozen or part of their tissues or blood has been
frozen,then it might be possible to make a clone.It would be impossible
to clone from an extinct animal because the whole nucleus will have
disintegrated,losing all structure and causing all the DNA to degrade.
• 5.Contributing to the improvement of gene:
• At present,nobody know what the genes are that give us
our individuality,our characteristics,the genes that are
associated with higher intelligence.
Conclusion
• In 21st century, genetic engineering is very important as
well as information technology. Cloning seems set to
become a vital technology for agriculture and medicine.
We should point out that ,with the careful continuation of
research, the technological benefits of cloning clearly
outweigh the possible social consequences. In their minds,
final products of cloning, like farm animals, and laboratory
mice will not be the most important achievement. The
applications of cloning they envision are not nightmarish
and inhumane, but will improve the overall quality of
science and life.
Member List
• Yip Ka Lai(Jocelyn)7B
• Ng Ka Ying(Christy)7A
• Yik Nga Che(GiGi)7B
• Chiu Chi Kit(Teddy)7B
Reference
• Http://sciam.com/1998/1298issue/1298wilmut.htm
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• Http://www.pathfinder.com/TIME/cloning
• Http://www.sciam.com/explorations/090297clone/
beardslep.html
• Http://www.newscientist.com/nsplus/insight/clone
/growyour.html
• Http://www.geocities.com/ResearchTriangle/Lab/2
705/speech.html