Реферат: Cloning Today Essay Research Paper Cloning Today
Cloning Today Essay, Research Paper
A clone is a group of organisms that are genetically identical. Most clones
result from asexual reproduction, a process in which a new organism develops
from only one parent. The one process of cloning, called nuclear transfer,
replaces the nucleus of an immature egg with a nucleus from another cell. Most
of the work with clones is done from cultures. An embryo has about thirty or
forty usable cells but a culture features an almost endless supply. When the
nucleus has been inserted into the egg cell, the cell is given an electric shock
to initiate the development. Traditionally this is the sperm?s role. In this
paper we will be discussing the advantages of different types of clones, such as
they are useful for research. We will also be discussing the disadvantages and
different techniques that result from the cloning of different organisms.
First lets start with the history of cloning. The modern era of
laboratory cloning began in 1958 when F.C. Steward cloned carrot plants from
mature single cells placed in a nutrient culture containing hormones. The first
cloning of animal cells took place in 1964. John B. Gurdon took the nuclei from
tadpoles and injected them into unfertilized eggs. The nuclei containing the
original parents? genetic information had been destroyed with ultraviolet light.
When the eggs were incubated, Gurdon discovered that only 1% to 2% of the eggs
had developed into fertile adult toads. The first successful cloning of mammal
was achieved nearly twenty years later. Scientists from Switzerland and the U.S.
successfully cloned mice using a method similar to Gurdon?s, but required one
extra step. After the nucleus was taken from the embryos of one type of mouse,
they were transferred into the embryos of another mouse who served as the
surrogate mother. This mouse went through the birthing process to create the
cloned mice. The cloning of cattle was achieved in 1988, when embryos from prize
cows were transplanted to unfertilized cow eggs whose own nuclei had been
removed. In 1993 the first human embryos were cloned using a technique that
placed individual embryonic cells (blastomeres) in a nutrient culture where the
cells then divided into 48 new embryos. These fertilized eggs did not develop to
a stage that could be used for transplantation into a human uterus.
Cloning can do many good things for our wild life and for our economy.
The process of cloning can save us a lot of money. A crop that is imported to
our country can instead be cloned here. It would also make the product cheaper.
Cloning would also develop stronger plants, resistant to disease, parasites, and
insect damage. With better plants, cloning could lead to more profit for farmers
and we could clone an abundance of trees. This would help the ecological health
of our planet. Cloning is good for out wildlife because with cloning it is
easier for us, as a nation and a world, to save many different types of
endangered species. We would also be able to keep a type of animal from
overpopulating its environment. We would be able to keep an animal within a
controlled number. Another possibility for cloning would be the creation of new
organs for someone who is in need of a transplant. The organ could be cloned
from someone matching the person?s type. This way people would not need to wait
for someone to die to find a replacement organ. These ideas have not been put
into effect yet, but that does not mean that they are far away in the future.
The ideas for cloning are infinite. There is no telling what the possibilities
can be. Edward Squires, an equine reproduction biologist at Colorado State, says,
“You could blow your mind thinking about the possibilities.” These are just a
few of the awesome possibilities in the world of cloning.
Now we will discuss some of the disadvantages of cloning. Cloning of
certain crops will increase the yield and quality. However this will also
increase the danger of a disease being able to destroy the entire crop. Cloning
destroys the genetic diversity of life. When everything is the same genetically
then it is more likely that the entire population will be wiped out by either
disease or predator. Ian Wilmut, a researcher in Roslin Scotland says, “The more
you interfere with reproduction, the more danger there is of things going
Is cloning ethical? That is a question that will be with us for a long
time. Are there benefits of cloning? The answer to that is a resounding yes. Is
there a bad side to cloning? This is Another irrefutable affirmative. Should we
Clone? This is where things start to get a little shaky. The answer is more of a
yea kind of, answer. Most scientists agree that we ought to do more research on
clones and even use some of the benefits that come through cloning. However,
most scientists also agree that lines should be drawn. Where should we raw those
lines? Everyone has an opinion in this category and they are all different. The
ability is there, at conception, to clone a human. Should this person be allowed
to grow and be a genetic backup for the “real” person. So if the “real” person
was to need a transplant of some organ there would be an exact copy ready and
waiting. This is just one of the ethical questions that need to be answered. The
question of cloning is no longer can we but should we.