Реферат на тему Cloning Essay Research Paper The biological definition
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Cloning Essay, Research Paper
The biological definition of a clone is an organism that has
the same genetic information as another organism or organisms
(”Cloning”, 1997). From this definition and from information
about the science behind cloning, my current view on cloning is
that it is ethical. This statement ignores information about how
we can misuse cloning and what consequences occur when the
procedure is unsuccessful. I currently do not think cloning
should be used until it is perfected. I doubt however that we
will allow cloning to be misused, and think most people would
probably have this opinion on cloning, but their lack of
knowledge on cloning, or their belief that cloning would be
misused, is the reason for differences of opinion. Thus, an
elaboration on the history, techniques, ethics, and reasons for
researching the technology of cloning is necessary.
The first thing that must be cleared up is what is cloning,
and what is a clone. A clone is an organism derived asexually
from a single individual by cuttings, bulbs, tubers, fission, or
parthenogenesis reproduction (”Cloning”, 1997). Parthenogenesis
reproduction is the development of an organism from an
unfertilized ovum, seed or spore (”Parthenogenesis”, 1997).
Hence, cloning, biologically speaking, is any process in which
production of a clone is successful. Thus, the biological term
cloning is the production of a genetically identical duplicate
of an organism. However, people can use the word cloning to
intend other meanings. For instance, we generalize many older
and new techniques as cloning. This is not a good practice
because these techniques are different and impose unique concerns
and issues.
In the world of scientific technology, cloning is the
artificial production of organisms with the same genetic
material. Scientists actually call the transferring of a nucleus
from the cell of one organism to an enucleated egg cell nuclear
transfer (Wilmut, 1997). This will produce an organism that has
the exact genetic material as that of the donor cell. Scientists
are using current techniques exceedingly more, and with a variety
of species. Astonishingly, more clones are present in the world
than one would think.
In nature, and even in the lives of humans, clones are
present. As stated earlier, a clone is an organism that has the
same genetic information as another organism. From this we can
say that cloning occurs with all plants, some insects, algae,
unicellular organisms that conduct mitosis or binary fissions,
and occasionally by all multicellular organisms, including
humans. Monozygotic twins, or identical twins, are clones of
each other. They have the same exact genetic information due to
the division of an embryo early in development which produces two
identical embryos. About eight million identical twins are alive
in the world, thus, already eight million human clones inhabit
the world. In unicellular organisms, a cell will produce two
daughter cells that have the same genetic material.
Today, the only cloning research is occurring in scientific
model organisms. These are organisms that research scientists
from around the globe have collected copious amounts of data.
All this data is necessary so that advancements in research can
continue more efficiently. The most common scientific models are
E. coli, mice, fruit flies, and frogs. The first organisms that
were cloned using nuclear transfer were frogs. This is because
they have large egg cells and scientists can obtain up to two
thousand of them from one ovulation. (McKinnel, 1979)
Successful cloning has occurred with livestock. The drive
toward success is not because livestock like cows and sheep are
model organisms. Instead, the farming industry has made and
continues to make a big effort toward finding a way to implement
the technique of nuclear transfer for livestock. Research in
cloning is also occurring in primates. The reason for studying
primates is the similarities with humans. This leads us to the
most talked about aspects of cloning, the use of the techniques
with human cells and eggs.
Throughout this century, conversation, novels, magazine
articles, newspaper reports, and movies have focused on the
implications of cloning humans. Part of this media creates
thoughts of a utopian society, while some a horrific world; the
majority of them being the latter.
For those who have had these frightening thoughts, Dr.
Richard Seed states he can accomplish the task of cloning a human
using nuclear transfer. Dr. Seed is a physicist who researched
fertility sciences in the 1980’s and is now specializing in
embryology. He states that he has set up a fertility clinic that
can conduct nuclear transfer. Dr. Richard Seed is creating an
uproar regarding the ethics of cloning. This is ironic because
cloning has occurred. (Flock, 1998)
Cloning of humans in a biological sense already has and is
occurring. Scientists are researching by splitting embryos to
execute experiments to find data relating to cell
differentiation, the use of stem cells, and genetic screening.
Amazingly, genetic screening is occurring in Britain quite often.
Fertility clinics aim this service toward couples where the
mother or father has a genetic disorder. A fertility clinic will
clone an embryo, then test it for genetic disorders. If the
embryo is tested negative for genetic disorders, then the
fertility clinic implants a clone of that embryo. This should
guarantee that the child will not have any genetic disorders.
(Benoit, 1996)
That is the current work with cloning. It is becoming a
part of our society already. Cloning is currently a technology
that many people could use. I believe it will become more
popular as prices for the technique decreases, and as the use of
cloning becomes increasingly acceptable. That is if we humans
consider cloning an acceptable technology, and that we would like
to use for the twenty-first century. Cloning has progressed so
quickly, few of us know if we should be even fooling with this
technology. Some scientists say that we put technologies to use
once the pros outweigh the cons. A good place for us to find
that information is to look at the past and current research
results with cloning and why scientists research it.
Amazingly, the first attempts at artificial cloning were as
early as the beginning of this century. Adolph Eduard Driesch
allowed the eggs of a sea urchin develop into the two-blastomere
stage. Then he separated it by shaking it in a flask and
allowing them to grow. The cells developed into dwarf sea
urchins. Driesch could not explain his experiments and gave up
embryology for philosophy (McKinnel, 1979).
The first implantation of a nucleus into an egg cell
occurred in 1952 by Robert Briggs and Thomas J. King in
Philadelphia. They had transferred the nuclei of Leopard Frogs’
eggs (McKinnel, 1979). The egg cells did not develop.
Successful cloning of embryo cells was accomplished later in the
1970’s by Dr. John Gurdon. The frogs did not develop beyond
tadpoles. In 1981, investigators announced they had transplanted
nuclei from mouse embryos into mouse eggs. However, other
scientists tried to duplicate the experiments, but found that
they fabricated the cloning results. (Kolata, 3 March 1997)
During the late seventies and early eighties, there were few
scientists still studying cloning. Many had predicted that it
was impossible to clone embryonic mammal cells. Few continued
with research. Many gave up and went into other fields.
However, some persisted and were rewarded for their efforts.
In 1984, Dr. Steene Willadsen announced that he had
successfully transferred nuclei from embryos of sheep to produce
clones (Kolata, 1997). He also was successful with cows and even
monkeys. He advanced his methods, and began cloning embryos that
were in the 64-128 cell-stage. This suggested that perhaps
nuclear transfer was possible with differentiated cells. More
exciting was when Dr. Neal First produced cows by nuclear
transfer from more developed embryos in 1994 (Kolata, 3 June
1997). Dr. First produced four calves. Two years later, Dr. Ian
Wilmut and Dr. Keith Campbell, of the Roslin Institute in
Edinburgh, Scotland, produced for the world Megan and Morag, the
first cloned sheep from embryo cells. Their new technique
involved the starving of the donor embryo. This would put the
cell in the right moment in the cell cycle, thus allowing the
genetic material to integrate more successfully with the egg
cell. This was the integral step of nuclear transfer. Dr. First
had executed the same step, but a laboratory staff member did it
accidentally, and First did not realize the significance of his
staff member’s blooper (Kolata, 3 March 1997). Dr. Wilmut and
Dr. Campbell became world famous. Their fame was not finished
yet however.
On July 5 at 4:00 P.M. lamb number 6LL3 (Campbell, 1997), or
Dolly, was born in a shed down the road from the Institute. She
weighed in at 14? pounds and was healthy. Scientists
accomplished this by using frozen mammary cells taken from a
six-year-old pregnant ewe and fusing them with an enucleated egg.
The trick to fusing the cells is giving a small electric current
to the petri dish on which the egg cell is. This stimulates the
egg much like a sperm would, and usually takes the genetic
material from the cell and becomes a zygote. They let this
zygote grow into an embryo, and then transplanted the embryo in a
recipient ewe, acting as a surrogate mother. This procedure
occurred late in January of 1996. This was the day of fusion date
for Dolly, which is the natural equivalent to a conception date.
An interesting note is that three different sheep were involved
in producing Dolly, versus the usual two or one (in-vitro
fertilization). Furthermore, the Roslin scientists used three
different breeds for each sheep to prove that the experiment was
a success. (Kolata, 3 March 1997)
After Dolly came other sheep, cows and even rhesus monkeys
cloned using similar techniques but with slight variations.
These cloned animals came from Roslin and many universities from
across America. They even produced clones which had genes that
would produce certain proteins. For instance, at Roslin,
scientists are trying to produce sheep that produce milk with
beneficial proteins for Cystic Fibrosis patients.(Kolata, 24
February 1997)
The goals and purposes for researching cloning range from
making copies of those that have deceased to better engineering
the offspring in humans and animals. Cloning could also directly
offer a means of curing diseases or a technique that could extend
means to acquiring new data for embryology and development of
organisms as a whole. Currently, the agricultural industry
demands nuclear transfer to produce better livestock. Cloning
could massively improve the agricultural industry as the
technique of nuclear transfer improves. Currently, change in the
phenotype of livestock is accomplished by bombarding embryos of
livestock with genes that produce livestock with preferred
traits. However, this technique is not efficient as only 5
percent of the offspring express the traits (Kolata, 25 July
1997). Scientists can easily alter adult cells. Thus, cloning
from an adult cell would make it easier to alter the genetic
material. A transgenic organism has had its genetic information
artificially altered. The goal of transgenic livestock is
to produce livestock with ideal characteristics for the
agricultural industry and to be able to manufacture biological
products such as proteins for humans. Farmers are attempting to
produce transgenic livestock already, but not efficiently, due to
the minimal ability to alter embryos genetically. Scientists can
harvest and grow adult cells in large amounts compared with
embryos. Scientists can then genetically alter these cells and
find which ones did transform and then clone only those cells.
Scientists also ponder the idea of cloning endangered species to
increase their population. The possibilities are endless.
However, we are actually doing much of this research for the
improvement of life for humans. Embryologist Dr. Steene
Willadsen, when talking of past research, stated, “I was checking
fences, looking for holes in the scientific fabric, ways to break
through what others considered dogma.” (Kolata, 3 June 1997).
Scientists foresee the cloning of pigs to produce organs
that humans will not reject (Wills, 1998). Also, as mentioned
earlier, livestock can produce biological proteins helping people
who have diseases including diabetes, Parkinson’s, and Cystic
Fibrosis (Kolata, 2 December 1997). Cloning also provides better
research capabilities for finding cures to many diseases. There
are also possibilities that nuclear transfer could provide
benefits to those who would like children. For instance, couples
who are infertile, or have genetic disorders, could use cloning
to produce a child. Equally important, women who are single
could have a child using cloning instead of in-vitro
fertilization. Nuclear transfer could also provide children who
need organ transplants to have a clone born to donate organs.
Cloning could also provide a copy of a child for a couple whose
child had died.
Cloning does offer some negative affects it could have to
life. The biggest problem with asexual reproduction is that
genetic diversity becomes limited. If a population of organisms
has the same genetic information, then the disease would wipe out
the population. This is because not one organism has an
advantage of fighting the disease over the other. The technique
of nuclear transfer is also early in its developmental stages.
Thus, errors are occurring when scientists carry out the
procedure. For instance, it took 277 tries to produce Dolly, and
Roslin scientists produced many lambs with abnormalities (Wilmut,
1997). This is the main reason science is holding out on cloning
humans. I also believe we should not attempt nuclear transfer to
produce an adult human until the technique is perfected.
Other arguments for cloning include if we are taking nature
into our own hands by cloning. Religious organizations consider
nuclear transfer to cause men to be reproductively obsolete
(Post, 1997). Religious groups claim that cloning defies the
rule or their belief that humans have souls. They also consider
cloning unnatural, and say we are taking the work of God into our
own hands. People question when we will draw the line for
getting involved in natural events (Bruce, 1998). There is also
a debate as to the moral rights of clones. Some say this will
occur because there is no birth of newness (Post, 1997). We
would not receive clones with such excitement as a child of a
couple who conceived naturally. If natural reproduction were to
occur, genetic variation would occur. They say cloning would
deprive someone to have any perception of uniqueness. They argue
that identical twins are not unique from each other. However,
they are new in genetic variation and unique from anything that
came before them. People also wonder what mental and emotional
problems would result if a clone were to find out that he or she
was cloned.
Although nuclear transfer produces clones, scientists
confess that they are not exact clones because the recipient egg
does not receive all the genetic information from the donor cell.
The genetic material that does not make it to the egg cell is
found in ribosomes which are present in the cytoplasm. In
addition, mutations can occur and genomic imprinting could cause
other differences.
Scientists even say monozygotic twins, or identical twins,
are not as identical as we thought. Scientists also predict that
dizygotic twins, or fraternal twins, would maintain more
similarities than clones. The reason seems that fraternal twins
grow a bond during their first nine months (Wills, 1998). This
is an example that genetics does not fully contribute to the
personality of a person. Time spent intrauterine for nine months
haves a greater effect than genetics is a good example.
Also, the statement that identical twins are unique and new
only in the sense of their new genetic combinations is absurd. I
know identical twins myself that are extremely unique, and
perhaps strive for differences. Constitutional law scholar
Laurence Tribe said that human cloning would ‘alter the very
meaning of humanity’ (Post, 1997). I think a clone would
especially find the meaning of humanity and become unique. I
think Tribe is confusing that we strive to be unique because we
are human not because we have chromosomal DNA that is found
nowhere else.
Sidney Callahan, a psychologist, argues that “the random
fusion of a couple’s genetic heritage gives enough distance to
allow the child also to be seen as a separate other” (Post,
1997). Yet I cannot stand that I look like my father when he was
my age, and currently I am under the impression that I was
conceived naturally. Thus I believe the old-fashioned way of
having kids is not giving me enough distance, so what is the
difference for a clone.
So anyone who argues that cloning disregards the laws of God
and the souls of humans, they should reconsider their views.
Cloning does not artificially produce copies of adult humans.
Nuclear transfer is the artificial making of an embryo that will
develop into an identical twin. No machine that can produce
carbon-copy humans when performing nuclear transfer is involved.
At this point, I believe we should not use cloning.
However, if we are to venture into cloning we must make many
precautions. I think the best way to do this is to research the
consequences. Yet, I do not believe cloning of animals is
acceptable. Thus, I do not think we should conduct cloning
experiment on animals. In summary, cloning is ethical, unless
there is lack of respect for the lives of animals and humans, and
for the ongoing inhabitation of life on earth.