Реферат

Реферат на тему Cloning 3 Essay Research Paper The biological

Работа добавлена на сайт bukvasha.net: 2015-06-15

Поможем написать учебную работу

Если у вас возникли сложности с курсовой, контрольной, дипломной, рефератом, отчетом по практике, научно-исследовательской и любой другой работой - мы готовы помочь.

Предоплата всего

от 25%

Подписываем

договор

Выберите тип работы:

Скидка 25% при заказе до 10.11.2024


Cloning 3 Essay, Research Paper

The biological definition of a clone is an organism that has the same genetic information as another organism or organisms. 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. In fact, I currently do not think cloning should be used until it is perfected. I doubt however that we will allow cloning to be misused. I 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, I will elaborate on the history, techniques, ethics, and reasons for researching the technology in cloning. 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. Parthenogenesis reproduction is the development of an organism from an unfertilized ovum, seed or spore. Hence, cloning, biologically speaking, is any process in which production of a clone is successful. Thus, the biological term cloning is the production of 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. 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 and 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 two thousand them from one ovulation. 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 momentous effort toward implementing 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 dreams 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. 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. In fact, 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. That is the current work with cloning. It is becoming very much 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 that we would like to use into the twenty-first century. Cloning has progressed so quickly, very 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 could let 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. 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 mouse nucleuses of embryos into mouse eggs. However, other scientists tried to duplicate the experiments, but found that they fabricated the cloning results. 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 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. 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 was 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 be accepted more successfully by 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. 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 (Kolata, 1997). 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 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.

After Dolly came other sheep, cows and even rhesus monkeys that were 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. 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. 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 to 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. Scientists foresee the cloning of pigs that will produce organs that will not be rejected by humans. Also, as mentioned earlier, livestock can produce biological proteins helping people who have diseases including diabetes, Parkinson’s, and Cystic Fibrosis. 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. 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, 1997). 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. This may be 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 animals or people. Religious organizations consider nuclear transfer to cause men to be reproductively obsolete. Religious groups claim that cloning defies the fact 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. There is also a debate as to the moral rights of clones. Some say this will occur because there is no birth of newness. 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 the fact that fraternal twins grow a bond during their first nine months. This is an example that genetics does not fully contribute to the personality of a person. The fact that time spent intrauterine for nine months had 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 very much 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 the fact 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 the fact 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, 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.


1. Реферат на тему Shock Treatment
2. Реферат на тему Political System Of Brazil Essay Research Paper
3. Сочинение на тему Жыццёвы i творчы шлях Максiма Багдановiча. Матывы яго лiрыкi
4. Реферат на тему 3 Lessons Learned Bird Sings Essay Research
5. Реферат на тему Расследование преступлений связанных с получением банковского кред
6. Реферат на тему Carl Jung Essay Research Paper Carl JungCarl
7. Реферат Налоговая система Кипра
8. Контрольная работа на тему Характеристика основных форм оздоровления физической культурой
9. Книга Вязание крючком. Обвязывание платочков кружевом с применением ИКТ
10. Реферат Отчет о прибылях и убытках 5