Cloning
Introduction
Cloning is the process of creating genetically identical copies of a biological being. It may be a replica of human, animal or body part. This topic is highly controversial, and new developments are continually being made. For this reason, this paper is intended to discuss the cloning, the basic cloning techniques, a brief background to cloning and the ethics associated, as well as the conclusion.
Definition and types of cloning
According to Wernig et al (2007) a clone is obtained by taking the cell nucleus of an organism and then implanting it into an egg cell. As it begins to develop to form an embryo, the clone is transplanted into a surrogate parent. Consequently, an exact copy of the cell nucleus donor organism is created. This donor could be human, animal or plant. This process has limitless benefits ranging from the ability to develop new human organs to replace new ones to the development of stem cell that are used to cure several ailments such as cancer, diabetes among others. This process therefore involves the copying of DNA fragments as stated by Starr, Evers and Starr (2009). There are three main types of cloning namely: gene cloning; reproductive cloning and therapeutic cloning.
Gene cloning
The basic unit of biological information in the body of an organism is called the gene. More often than not, a gene is a code for a protein product, which is first transcribed into an RNA messenger and later transformed into the protein product. Other genes like the Ribosomal RNA and the transfer RNA are stable RNA (Lodge, Lund and Minchin 2007). In human beings for instance, the genetic information is carried in 23 pairs of chromosomes.
Gene cloning is the process by which the desired gene is traced and duplicated from DNA extracted from a donor organism (Lincoln 2001). This extraction of a DNA is in the company of all the genes of the organism and so the genetic engineer must search and identify a gene containing the proteins of interest. This identification requires the formation of genetic libraries to catalog the DNA of the organism. Brown (2007) identified the steps involved in gene cloning as: first, the isolation of the DNA from the donor organism of interest and placed in a circular DNA by the name of a vector to generate a molecule of the DNA that is recombinant; the vector is then used to transfer the gene into a host cell, can be any living cell; inside the host cell, the multiplication of the vector occurs yielding mass identical copies of self and of the genetic make up; the division of the host cell takes the recombinant DNA to the progeny where additional multiplication occurs; as a result of numerous divisions, a clone or colonies of identical host cells are obtained. At this point, the gene of the recombinant cell is in each clone and in now cloned.
Reproductive cloning
According to Houdebine (2003) this is the production of a genetic identical of an organism that is. For instance, human clone would be genetic identical of a human that is. In this process, the somatic cell nuclear transfer-SCNT (2011) is the most popular technique where the nucleus of a body cell is placed into an egg, without a nucleus as well, to generate a clonal embryo, which with the use of chemicals and/or electricity is activated to start developing and later, the cloned embryo is situated in the uterus of a female organism which develops into a clone of the cell nucleus donor organism and with identical genes. So far, no human child has been cloned using SCNT.
Therapeutic cloning
This is the form of cloning mostly associated with the curing of diseases (Cohen 2002). The process is similar to that of gene cloning except that the resultant embryo is allowed to grow to at least 14 days, when its stem cells would be taken out and encouraged to develop into a part of human tissue or entire human organ for relocation. Finally, the result would be a human replacement organ or a piece of the nerve tissue or even a piece of skin. Despite numerous attempts, the first triumphant application of therapeutic cloning was achieved in the year 2001 by a biotech company in Worcester called Advanced Cell Tech (Cohen 2002).
Background information
The earliest dated discovery of cloning dates as early as 1902 by Sutton. As published in his paper on Morphology of chromosomes, he hypothesized that chromosomes hold the elements responsible for inheritance in any given cell and that this chromosomes occur only as unique and various pairs inside the part of the cell called nucleus. He found out that, the characteristic of the chromosome as the cell divided was the basis for the Mendelian Law of Heredity using grasshoppers in his research. These ideas later yielded the Chromosomal theory of heredity which is a hallmark in genetic understanding (thinkquest 2011).
The second major milestone was by Hans Spemann in the same year who split a double-celled embryo of a salamander after which each cell developed into an adult salamander providing prove that genetic information is indeed present in early embryo cells and this information plays a part in the creation of a new organism (thinkquest 2011).
This was useful in disapproving the Weismanns proposition that at every cell division, there is a decrease in genetic information. From his repeated experiments of splitting more advanced embryos, he concluded that the determination stage of embryo development resulted to the determination of specialization of the cells in the embryo (thinkquest 2011). In addition, Spemann found out that it was only prior to this stage that a full organism could be created.
The other notable advancement of cloning was by John Gurdon from OxfordUniversity who after using the nucleus of an entirely differentiated cell from the intestines of an adult had cloned South African frogs (thinkquest 2011). This was milestone in proving the failed clone results of Briggs and King’s experiment using differentiated cells of a tadpole in 1952. In addition, Gurdon’s experiment served to disapprove the fact that cell specialization reduced its genetic potential.
Nonetheless, this findings were discovered by smith as being similar to the same ones identified by Briggs and King who discovered that the use of a cell nuclei from differentiate cells would accomplish cloning. Further criticism was from Di Berardino who concluded that the nuclear transfer damaged the transferred nucleus hence was a poor way of if a specialized cell contained information about the complete organism development. Amidst all these, Gurdon’s discovery was a hallmark in the cloning subject (thinkquest 2011).
In his speech entitled ‘possibilities for human biology in the coming 10,000 years’ Haldane, a British biologist was the first to use the term cloning to describe the process of genetic information transfer which no other scientist had earlier on used. The other milestone was in the creation of mice with just one parent by Karl Illmensee in the company of Hoppe peter. The two carried out two experiments in which they developed a mouse with just a father and another with just a mother parent (thinkquest 2011). They did this by separating the gene of the father and mother immediately after fertilization making up two pronuclei within the egg cell after which he separated one and copied the other using special enzymes and the egg now held only the genes of one parent (thinkquest 2011).
The greatest milestone of all was the development of cloning as illustrated by Eenennaam (2008) was in 1996 when the first animal was cloned from an adult cell this was called adult or somatic cell cloning. In this case, the somatic cell nucleus is extracted and inserted into a fertilized egg whose nucleus was also removed. This egg is now nurtured while dividing into an embryo and later placed into a surrogate female from where it develops.
According to Helium (2007) cloning is not completely a production of a duplicate organism but the production of an organism with different qualities from the original since it is developed from inside another mother who is unlike the real. In this case, the morality associated with cloning is put to question as to why it would be necessary then to bring such a creature into the world where the love and affection of its mother is unattainable. For some reasons, the laws in some states have totally prohibited the cloning of humans unlike that of animals.
Different people feel that cloning is morally and ethically wrong due to believe that life begins at conception and by removing the nucleus of a fertilized egg, one is in fact committing murder and this is ethically and spiritually wrong. Other including scientist argue that life begins after birth since this is the only time the new born is almost independent from the mother.
Conclusion
Cloning has been around for a long time, however it is very controversial. Cloning has many applications and can help shape our future, and potentially save thousands of lives.
References
Brown, T., (2007). Gene Cloning and DNA analysis. Blackwell Publishing. Oxford: UK.
Cohen, D., (2002). Cloning. Twenty first Century books. Brookfield: USA
Eenennaam, V., (2008). Livestock engineering.University of California. United States of America: USA.
Helium, (2007). Assessing legal Implications of Cloning. Retrieved on 12-05-2011 from http://www.helium.com/items/646693-assessing-the-legal-implications-of-cloning?page=2. Last updated on 14-10-2010
Houdebine, L., (2003). Animal Tran genesis and Cloning. John Wiley and sons, Inc. Chichester: England.
Lincoln, (2001). Gene Cloning. University of Nebraska. ArBiosafety education center. From http://agbiosafety.unl.edu/education/clone.htm.
Lodge, J., Lund P., and Minchin S., (2007). Gene cloning. Taylor and Francis Group. New York: NY.
Starr, C., Evers C., and Starr L., (2009). Biology. Cengage Learning. Belmont: CA.
The SCNT (2011). Reproductive clonining. Retrieved on 12-05-2011 from http://www.geneticsandsociety.org/section.php?id=16 last updated on 2011.
Thinkquest, (2011). Projects by students. Oracle Foundation. Retrieved on 12-05-2011 from http://library.thinkquest.org/24355/data/details/1977.html last updated on 2011
Wernig M., et al (2007). Home made Stem Cells. University of Arizona College. From http://student.biology.arizona.edu/honors2007/group01/home01.html.
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