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Cloning Cloning as a concept has been recently launched by scientists and adopted by contemporary popular language. In 1997 biologists together with genetic and medical specialists of Roslin University in Scotland managed to produce the cloned sheep Dolly and officially publicized its existence. [ 2 ] Since those times the idea of cloning became a subject of intense interest and permanent discussions all around the world. For the last decade it remains to be one of the most emotional and controversial issues of humanity. Though cloning came into the public eye rather recently, the history of relevant experiments and researches on reproductive opportunities and practical techniques goes back to early XX century. In many progressive countries leading genetic and biology scientists have been studying the problem, analyzing and carrying out tests on cloning. Finally, in 1952, much long before Dolly's successful coming to the world, a pilot cloned organism, an animal, was received after long experiments on replacement of embryonic cells. [ 2 ] Lately, up-to-date technology of nuclear transferring has developed enough, and it allowed scientists to clone a great variety of different mammals, such as mice, cats, rabbits, sheep, pigs, or goats.
Many of those organisms are still alive, but the majority of them died; some were eliminated by specialists, like well-known Dolly was. But it is interesting that numerous efforts on cloning of some special spices of animals, like dogs, monkeys, or horses, completely failed. Scientific explanation of this can be found in supposed biological receptivity to nuclear transfer, observed in above mentioned types of animals. [ 2 ] In its purest meaning cloning is a component of professional terminology of genetic scientists, which specifies a chain of scientific experiments resulting in receiving of duplicate of initial biological material. Scientific process of cloning can be understood as carrying out of forced reproductive procedures in a singular biological tissue without using of natural sexual contacts.
Therefore, only one parent or donor, who can produce one or more offspring, is required for cloning. And in the end of the experiment the received clones will have gender and genetic compositions absolutely identical to those of their ancestor. [ 1 ] Consequently, cloning allows producing of new examples of biological tissues or even whole organisms, which will be absolute genetic copies of already existing ones and have completely same biological and other natural characteristics. From the scientific point of view, experimentally it can be done by replacing of the nuclei with genes in cells, forming the body of an organism, with nuclei of a fertilized egg. [ 4 ] In modern scientific technology cloning occupies a very important place and serves as a source of different significant discoveries: scientific, experimental, practical, medical, etc. Cloning helps to receive answers on lots of questions about our genetic nature, diversity, and many other characteristics. [ 1 ] Recently specialists classify three principal types of cloning: reproductive cloning, DNA (recombinant or molecular) cloning and therapeutic cloning. [ 2 ] Reproductive type of cloning is exactly that one, which received the most public attention and which we all know about. It means experimental producing of a whole living organism with the same DNA composition as already existing donor-organism has. Scientific background of this type of cloning is called somatic cell nuclear transfer.
The process consists of removing genetic material from an egg and placing genes from another donor cell. The procedure must be accompanied with additional stimulating of cell division. [ 4 ] If the first stage of the experiment is successful, the cloned embryo must be placed into a female host to carry on its development and growth. That is how Dolly the cloned sheep has been produced. Actually, Dolly was an extraordinary step forward in the whole science, because its existence proved the possibility to replicate an entire animal, using genetic material from only one parent cell. [ 1 ] The type of recombinant DNA cloning has much more complex scientific background and technological process. It can be practiced only in laboratories of molecular biology.
The concept of this type of cloning is also concentrated on transferring of different fragments of genetic material of biological organisms to another genetic elements (like, for example, self-replicating bacterial plasmid). In other words, recombinant cloning can be imagined like a process of cloning of genes, or chromosomes. Carrying out of relevant tests and experiments seems to be critically important, first of all, for improvements and progress of methodical researches and studies at the field of molecular biology. [ 2 ] Therapeutic type of cloning helps to reveal and analyze various biological characteristics of human embryos, together with specific scientific details of their productivity. Procedure of this kind of cloning is aimed on receiving of so called stem cells by their extraction from the fertilized egg during the time of its development. The main purpose of such experiments is not producing of a human or an animal clone, but rather examining and analyzing the development of an organism in general. [ 2 ] In addition, contemporary genetic specialists and researchers found out a huge prospective potential of stem cells technology for creating a cure for many complicated diseases, like some types of cancer or Alzheimer's disease.
Besides, there is one more very important application of these biomedical experiments, directed on future potential use of cloned tissues for transplantation of human organs. That is why therapeutic cloning is supposed to become a major and irreplaceable technology of receiving healthy tissues or entire biological organs. [ 2 ] Therefore, developing scientific knowledge of issues of cloning is very promising at numerous fields of therapeutic practice and analytical science. Only molecular technology of cloning opens wide new horizons in biomedical and genetic engineering. For example, recent discoveries in genetics, connected with experiments on cloning, proved to be an upturn in creating of the technology of modification and correction of faulty genes in the cells of biological organisms. Or, the other genetic combining tests helped to learn the possibilities of making changes in different characteristics of biological organisms and tissues (like changing taste or density, or increasing immunity for some diseases, etc. ). Such experiments open the ways of creating more efficient or more unique characteristics of biological organisms.
Researches in reproductive cloning became very handy and important in biology for increasing of the population of some groups and species of animals, especially those ones, which are about to vanish, or which are difficult to breed. [ 2 ] But it is worth to mention that modern technologies of cloning are connected with a lot of problems and risks. Firstly, experiments on cloning are very complicated, expensive and can be characterized by very high rate of failure. Statistically, only about 3 - 10 % of all the experiments resulted in successful producing of clones. Bad compatibility of the egg and replaced nucleus, failures during the implantation, problematic pregnancy, etc.
can be named among the reasons of such ineffectiveness. [ 2 ] Moreover, in the majority of cases, problems connected with survival and normal development of cloned organisms can occur. As a rule clones have invalid immune system, fast reaction on outer infections, or other similar disorders. Besides, organisms of clones are very rapid in changes: they may look good and healthy, and then suddenly die in some hours. Cloned living organisms are mostly considerably bigger in size, than their usual relatives, and such syndrome frequently causes different diseases or malfunctions. [ 2 ] Besides, frequently numerous problems are caused by different abnormal genetic processes. As cloning is an artificial, forced process, there are no usual natural reactions in replaced nucleus of a cloned embryo. That is why during the tests on cloning scientists try to teach cloned cells to react and develop naturally, but such efforts are not always successful.
Errors in genetic material often take place; that results in abnormal or faulty forming of the cloned embryo. Naturally, a new organism must be created with the participation of two parents and receive genes from both of them, not only one. But in cloning there is no process of choosing of DNA, because there is just one donor and clones receive definite set of DNA from that very donors cells. [ 2 ] Certainly, there is significant legal, ethical and social background for issues of cloning. Nowadays the problems of legislative regulation of cloning, its legacy and various influences on social life are under active discussion. And the most debatable and controversial point is, undoubtedly, cloning of humans. The first successful attempt to produce a human clone took place in the year 2001.
It was a very complicated experiment: bio-genetic specialists worked over transferring of genetic material from the eggs of eight female donors. They used a usual skin cells to receive nuclei. Scientists sophisticated equipment included a 2 / 10, 000 th of an inch wide needle. Technically and physically it was very hard to start reproductive process in the eggs, and during the experiment just one of eight eggs could divide into six cells. [ 2 ] The aims of such researches were announced as therapeutic discoveries. But the very thought about the opportunity to produce a human clone created big reaction in public opinion. [ 3 ] Many genetic and biomedical specialists consider reproductive cloning of humans to be firmly unethical, though they admit its importance and usefulness for science and researches. They emphasize that the most dangerous and risky issue is mental development of human clones, which is absolutely unpredictable and very highly valuable from the positions of ethics and moral.
These risks are too big and can not be ignored. That is why cloning of human can be called as ethically irresponsible action. [ 3 ] Progress and achievements of cloning technology made a huge influence on modern science and the entire society. Nowadays it is really important for all people around the world to learn and to understand all possible consequences of developing cloning technologies, together with all related influences of them on our existence, and face up own responsibility for coming generations, for their future safeness and harmony. Bibliography: B eddington, R.
Cloning. National Institute of Medical Research, 1997. Mill Hill Essays. Retrieved February 13, 2005 from web Cloning Fact Sheet. Oak Ridge National Laboratory.
July 09, 2004 Human Genome Project Information. Retrieved February 13, 2005 from web Reaves, J. The Scientists Speak: No Human Cloning. Time. January 18, 2002.
Time Online Edition. Retrieved February 13, 2005 from web What Is Cloning? Genetic Science Learning Center. 2004. Database of University of Utah. Retrieved February 13, 2005 from web
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Research essay sample on Type Of Cloning Cloning Of Humans
