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Cloning The concept of cloning, introduced by scientists and adopted by modern popular vocabulary, is one of the most emotional and controversial issues. Cloning became a subject of worldwide public interest and discussions in 1997, when scientists of Roslin University produced and demonstrated Dolly the cloned sheep, though the history of cloning experiments and tests on reproductive techniques goes back for more than a century. Cloning used to be an item of usual terminology of scientists, defining various procedures of duplicating of biological material. Cloning means carrying out of reproductive process without sexual contact, so only one ancestor who can produce one or more offspring is required. That is why clones have the same genetic composition and gender as their parent. In other words, cloning gives the opportunity to create one more living organism, genetically absolutely identical to already existing one, with the same biological characteristics.
Practically it can be attained by replacing of the nucleus with genes in cells of forming the body of an organism with nucleus of a fertilized egg. Scientists of all around the world have been carrying out experiments on cloning, and in 1952, long before Dolly, the first cloned animal was produced from embryonic cells. Recently with the help of modern technology of nuclear transferring scientists managed to clone a variety of mammals, like pigs, cats, rabbits, mice, sheep, and goats. Many of those examples are still alive today, and much many of them died, or, like famous Dolly, they were put out of pain. Also, numerous attempts to clone some definite spices, like dogs, horses, or monkeys, unfortunately, failed. Specialists explain this with biological receptivity of such spices to process of nuclear transfer.
In modern scientific technology cloning received proper development and recently it is used with different purposes: scientific, experimental, practical, medical. Cloning gives answers on many questions about our genetic nature, characteristics and diversity. Specialists define three different types of cloning: reproductive cloning, DNA (recombinant or molecular) cloning and therapeutic cloning. Type of cloning that gained the most public attention is reproductive type. It results in producing of an organism, which has the same nuclear DNA composition as already existing organism. Scientific technology of reproductive cloning is called somatic cell nuclear transfer: this process includes removing of genetic material from an egg by transferring of genes to that egg from another donor cell and further stimulating of cell division.
After proper development of the cloned embryo, it is placed into a female host to continue development. That is how Dolly the clone was created. Scientifically, Dolly was a remarkable breakthrough, because its existence showed that it is possible to use genetic material from only one adult cell to reproduce an entire new creature. Recombinant DNA cloning has more complicated scientific background and technology; it is being practiced in laboratories of molecular biology institutions.
The process is again in transferring of fragments of genetic material of biological organism to other genetic elements, like, for example, self-replicating bacterial plasmid. Therefore, recombinant cloning results in cloning genes or DNA chromosomes. Performing of such experiments is very important, first of all, for improvements and advantages of methodical researches and studies in modern molecular biology. Therapeutic cloning helps to examine biological characteristics of human embryos and particulars of their productivity. Technology of this type of cloning is directed on producing of so called stem cells, which can be extracted from the fertilized egg during its development. The main purpose of these experiments is not in creating of human clone, but in analyzing and studying of human development.
Besides, modern researches of stem cells revealed promising potential of such technology in treating of many difficult diseases, like cancer or Alzheimer's. Also there is one more direction of biomedical experiments directed on prospective use of cloning for transplantation of human organs. Thus, developing cloning technology is promising on many fields of science and social practice. Molecular DNA technology opens new horizons in genetic engineering. New achievements in genetic therapy are helpful in developing of processes of making corrections in faulty genes in the cells of biological organisms. Experiments with genes combinations can improve the characteristics of organisms (like taste for food or immunity for definite diseases for animals) and allow creating more efficient ones, or ones with special abilities.
Researches in reproductive cloning are important for increasing of population of one or another group of animals, which are endangered or difficult to breed. Therapeutic cloning may become significant and irreplaceable technology for producing of biological organs or healthy cells. Technology of cloning is connected with a great deal of problems and risks. First of all, cloning experiments are hard, expensive and have high rate of failure. Only less than 3 - 10 % of all the experiments brought to creating of living clones. Reasons of such insufficiency can be the following: bad compatibility of egg and new nucleus, failings of implantation or pregnancy, etc.
Besides, problems may happen with further development of cloned organisms. Usually they have damaged immune function, low receptivity to different infections, or other disorders. Cloned animals tend to be larger, than their natural counterparts, and such so called Large Offspring Syndrome may cause various malfunctions in organisms. In addition, changes in organisms of clones are very fast, cloned animals may appear healthy in the morning and strangely die in some hours. Frequently problems happen because of abnormal genetic processes. Replaced nucleus of a cloned embryo does not have the same natural programming.
During the experiments scientists do such programming, but it is not always successful, and errors of genetic material may take place, which cause faulty or abnormal development of the embryo. Naturally embryo is being created by two parents and it receives genes from both of them, but the process of choosing of DNA is absent in cloning, because the parent is only one and clone receives DNA from a single donor cell. Finally, cloning experiment may also fail because of telomere differences, caused by age of donor cells. Undoubtedly, issues of cloning have legal, ethical and social background, the matters of governmental regulation of cloning or its influence on social life are recently under debates. But the most controversial question is connected with cloning of humans. At the end of 2001 the attempts of American biotechnology scientists to clone first human embryo were crowned with success.
The technology was very complicated: specialists transferred genetic material from eight womens eggs and usual skin cell was used as donor of nucleus. The equipment they used during the experiment included a needle of 2 / 10, 000 th of an inch wide. Technically it was difficult, but it was much harder biologically to make eggs start dividing, and only one of eight eggs could divide into six cells. The purpose of these experiments has been announced as therapeutic researches, but the opportunity to receive human clones caused big resonance in public opinion. Specialists of American Medical Association and other scientists expressed their viewpoints against reproductive cloning of humans.
They consider it to be strictly unethical, though possibly useful for science. Specialists underline that the most risky point of human clones is their mental development, unpredictable and morally highly valuable. With so many hazards human cloning is dangerous and ethically irresponsible. Recently, the Congress is working over laws which will prohibit human cloning. Development of cloning made considerable impact on modern society. And it becomes very important for all members of it to study and analyze all possible effects of cloning technologies and connected issues on our life and form own opinion with full responsibility for future safeness and peace in the world.
Bibliography: B eddington, R. (1997). Cloning. National Institute of Medical Research, Mill Hill Essays. Retrieved October 27, 2004, from web (N.
d. ) Cloning. Eureka! Science Corp, Retrieved October 27, 2004, from web Flash, M. F. (1997).
Is Human Cloning the First Step Toward Eugenics and Immortality? Arlington Catholic Herald, Inc Retrieved October 27, 2004, from web Reaves, J. (2002, Jan 18). The Scientists Speak: No Human Cloning. Time, Time Online Edition. Retrieved October 27, 2004, from web (2004).
What Is Cloning? Genetic Science Learning Center. Database of University of Utah. Retrieved October 27, 2004, from web
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Research essay sample on Cloning Of Humans Type Of Cloning
