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Реферат на тему Cloning 8 Essay Research Paper Cloning Cloning

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Cloning 8 Essay, Research Paper

Cloning Cloning is the production of a group of genetically identical cells or organisms, all descended from a single individual. The members of a clone have precisely the same characteristics, except where mutation and environmentally caused developmental variation have occurred. The DNA is precisley the same and they are only differentiated by their experiences in which dictate their personality. There are some types of natural cloning that nature displays. Some animals have tremendous powers of Regeneration. If the body of certain starfishes is cut up into its five arms, each arm will regenerate a complete individual. Another type of asexual reproduction found in all animals, human beings included, is the formation of identical twins, triplets, and so on. Identical siblings constitute a clone. The growth of a tumor in the body of an individual is, in effect, the formation of a clone of malignant cells. Humans have learned from nature and started their cloning saga also. In one method of artificial cloning used in plant breeding, cells are cut from a plant and placed in a flask with a nutrient medium. The cells grow and divide, forming embryonic tissues that are transferred to soil, where they produce complete plants. Grafting is another method of cloning used in Horticulture. Matching cuts are made in the stems of two plants, which are then fitted together so that their transport systems are in contact. The wounded area heals, and the two stems become a single physiological unit. All the McIntosh apple trees now in use and many other fruit varieties have been derived by grafting from single ancestral trees. “Nuclear transplantation,” in which nuclei from cells of one individual are transferred to unfertilized eggs whose nuclei have been removed, is one method of artificial cloning in animals. All the transplanted nuclei are generally identical, and therefore the resultant individuals constitute clones. Great concern has been voiced over the use of Genetic Engineering for humans and animals. One concern is that transgenic animals carry pathogens of their own that may be transferred to humans with unknown consequences. The 1993 cloning of nonviable human embryos has raised considerable ethical questions about the uses of this technology. The regulatory agencies must establish ground rules for the use of these technologies and products. At the same time, genetic technology is not an unmixed blessing. The potential abuses of genetic technology warrant our careful and considered attention. Linkages between genetic screening and abortion, testing and discrimination, and the supposedly positive and negative aspects of the discredited pseudo-discipline of eugenics represent important subjects meriting wider public discussion. No less important are the implications of patenting human genes and genetically engineered animals. Unfortunately, due to the rapid expansion of the technology, we do not have the luxury of discussing these issues in a leisurely manner or one at a time. The breathtaking pace of technological advancement requires that the cultural discourse and the public policy with respect to genetics must develop simultaneously. Human genetic material is routinely patented. In July 1990, the California Supreme Court ruled that a patient whose diseased spleen had been used to produce patented cell lines had no right to the millions of dollars potentially resulting from the sale of pharmaceutical products derived from his spleen. By September 4, 1993, the National Institutes of Health had filed for patents on 6,122 gene fragments. Although patenting of “gene fragments of unknown biological function” is presently disallowed, who knows what the future holds? Most of this territory is uncharted. Boston University Professor of Health Law George Annas has asked, “Since cloned human embryos are not persons protected by the Constitution and theoretically at least could be as ‘immortal’ as cloned cell lines, could a particularly ‘novel’ and ‘useful’ human embryo be patented, cloned, and sold?” Our candid presupposition is that both humans and animals are more than the sum of their genetic code. In our view, genetic patenting of Homo sapiens is, however, a separate issue in some respects from patenting other organisms. Both are problematic, but for slightly different reasons. The explosions of our capabilities without a concomitant expansion of ethical reflection demands that we resist the temptation to apply unthinkingly every technology the day it is conceived. We need careful investigation of alternatives to human and animal patenting. A blind frenzy of patenting is far more dangerous than a strict prohibition. We need to strive for and cultivate measured judgments and restraint with respect to the new genetics. Recognizing that a moratorium on patenting genes may put some potential treatments and cures for genetically linked illnesses at risk. Also, many cloned animals have oversized features, although whether that holds true for humans is unknown because none have ever been cloned. The possibilities of reasons to clone are almost endless. You could clone to have organs for transplants. Parents could build a family of clones born at different times. Or, as Shannon Brownlee said, “A bizarre possibility to consider is that a woman conceived from a split embryo could give birth to her twin.” Cloning could give infertile couples a chance to have children. Humans can be cloned. They have been cloned. Naturally, of course. In reference to identical twins. Outside of that, no human has ever been artificially cloned. One attempt at splitting an embryo in 1993 came very close, but was not successful. Although humans haven’t ever been cloned, several animals have, all in recent months. The more publicized cloning was of Dolly the sheep. The cloning that also occurred, but had much less television coverage was that of a monkey. The monkey is even more genetically close to humans. After that, several other attempts have been made to clone cows, and although many embryos have been made, no cow that we know of has been successfully cloned. Even to clone Dolly, it took 277 attempts before a success. Attempts to clone humans are also currently being cut short. A British ban on cloning, a ban on cloning currently in the works in the U.S., and a current ban on the use of federal money for then research of cloning humans all make it tough. In addition to that, both of the two ways of cloning, splitting an embryo, and implanting genetic cells into an egg are hard to do, expensive, and dangerous. Also, even if the genes are the same, there will be small differences in the body, environmental differences, and large differences in the brain and the way it develops make true cloning impossible. Habits learned during childhood would also be significantly different. After all, although many scientists think cloning will someday be possible, many also think it would be unethical to try. With all of these possibilities, the social and economic repercussions need to be taken a look at and then a comprehensive decision by the scientific community needs to be reached. Bibliography Fincham, J. R. S., and Ravetz, J. R., Genetically Engineered Organisms (1991) Jackson, J. B., Population Biology and Evolution of Clonal Organisms (1986) Steinberg, M. L., and Cosloy, S., The Facts on File Dictionary of Biotechnology and Genetic Engineering (1994). Baines, W., Genetic Engineering for Almost Everybody (1988) Barton, J.H., “Patenting Life,” Scientific American, March 1991 Erlich, H.A., PCR Technology (1989) Melton, D.A., Antisense RNA and DNA (1988) Setlow, J., Genetic Engineering, vol. 11 (1989) Williams, J., and Patient, R., Genetic Engineering (1989).


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