The third procedure is therapeutic cloning, also called “embryo cloning”. The process involves the creation of human embryos, designed specifically to harvest stem cells. Stem cells are important because they allow scientists to generate any cell in the human body. Unfortunately, the extraction of stem cells destroys the embryo, raising many ethical concerns. Researchers hope that stem cells would be used some day to treat Alzheimer’s and other diseases.
An additional cloning technique is recombinant DNA technology or DNA cloning. It is “the transfer of a DNA fragment of interest from one organism to a self-replicating genetic element such as a bacterial plasmid”. The technology has been around since the 1970s and is mainly used to copy genes and other pieces of chromosome. To clone the gene, a DNA fragment containing the gene is isolated from the main DNA strand using enzymes and then injected into a bacterial plasmid that has been cut with similar enzymes. Following injection into the host cells, the DNA can be reproduced countless times. Besides plasmids, viruses, bacteria artificial chromosomes, and yeast artificial chromosomes can be used as cloning host cells (“Cloning Fact Sheet” 2).
The best known form of cloning is somatic cell nuclear transfer (or reproductive cloning), the technique used to clone Dolly (“Cloning Fact Sheet” 3). In this process, scientists transfer genetic material from a somatic cell into an enucleated egg cell (a cell with its genetic material removed). There are two methods that enable scientists to merge the two cells. In the first procedure, the fusion method, scientists place both cells in contact with each other. An electrical pulse is applied and forces the somatic cell’s nucleus into the enucleated cell. In the injection method, the second process, scientists inject the nucleus directly into the enucleated cell (“Cloning” 3).
Though the efficiency of somatic cell nuclear transfer is low, “technical developments are increasing embryo and fetal development rates” are making this method the most promising. Though knowledge of nuclear transfer is in its infancy, new research is allowing scientists to gain a stronger understanding of the cloning process. Ultimately a full understanding of somatic cell transfers will “likely open the full potential of the cloning technology for medical, agricultural, and preservation applications and remove many of the existing risk factors” (Dinnyes et al. 87).
Applications of Cloning Technology Despite the problems, scientists believe that cloning can bring revolutionary changes in ecological, agricultural, and medical fields. For example, the cloning of endangered animals can prevent their extinction. In 2001, the first clone of an endangered animal, a young gaur, was born. Though it died two days later from a bacterial infection, the birth of the gaur proved that it was possible for scientists to clone animals (“How Cloning Works” 1). Researchers also hope to revive extinct animals one day using cloning technology. From an agricultural standpoint, cloned animals could produce higher yields of meat or milk and aid in the development of new drugs. In Scotland, for example, cloned sheep produce milk with a protein that helps in the treatment of hemophilia (“Cloning” 5).
However, the widest application of cloning technology is in the medical field. Cloning can be used to create new technologies involving gene therapy and genetic engineering. The boons that gene therapy could bring to the human civilization would be incredible. The therapy could be used to treat and prevent certain genetic diseases, greatly improving healthcare. Embryo cloning would be used to create new organs and treat degenerative diseases such as Alzheimer’s or Parkinson’s. The cloned organs could also be used in transplants, reducing the need for organ donations.
Unfortunately, more research needs to be done before these applications become reality. Cloning is currently expensive and highly inefficient: “more than ninety percent of cloning attempts fail”. Cloned animals are also more susceptible to disease and other disorders. Studies show that cloned mice have poor health and die early (“Cloning Fact Sheet” 4-6). Unless many of the problems with cloning are solved, the benefits will never be fully realized.
Conclusion
Cloning remains one of the most controversial issues in today’s society. Though cloning has been around since the earliest parts of human civilization, the technology to harness its potential has only been around for a few years. Through intense study, researchers have discovered numerous ways to clone cells. Over the last few years, scientists have discovered new and exciting ways to utilize the technology. Medical applications of cloning have the potential to revolutionize the healthcare system. Overall, cloning will herald a new age of medicine.
Bibliography
1. Brem, Gottfried and Birgit K�hholzer. “The Recent History of Somatic Cloning in Mammals.” Cloning and Stem Cells. Volume 4 Number 1. http://rudolfo.ingentaselect.com/vl=2201898/cl=11/nw=1/rpsv/cw/mal/15362302/v4n1/contp1.htm. 07/11/03.
2. “Cloning,” Microsoft Encarta Online Encyclopedia 2003. http://encarta.msn.com/encnet/refpages/RefArticle.aspx?refid=761567589 1997-2003 Microsoft Corporation. 07/07/03.
3. “Cloning Fact Sheet.” Human Genome Project Information. http://www.ornl.gov/TechResources/Human_Genome/elsi/cloning.html. 07/07/03.
4. Dinny�s, Andr�s; Paul De Sousa; Tim King; Ian Wilmut. “The Somatic Cell Nuclear Transfer: Recent Progress and Challenges.” Cloning and Stem Cells. Volume 4 Number 1. http://rudolfo.ingentaselect.com/vl=2201898/cl=11/nw=1/rpsv/cw/mal/15362302/v4n1/contp1.htm. 07/11/03.