Cloning: The New Age of Medicine.

Joseph Kundukulam

Cloning: The New Age of Medicine

Introduction

One of the major issues in modern society is the idea of cloning. Even today, cloning still generates strong controversy throughout the country. Advocates claim that cloning will create major advances in the medical field. Critics believe that cloning is a direct violation of God’s will. Whatever the case may be, it is important to gain a strong understanding of the cloning process. This report will provide information about the history of cloning, major techniques, and popular applications of cloning technology.

History

Though cloning has gained popularity in recent times, humans have been practicing the technique for thousands of years. The definition of cloning is “creating a [identical] copy of living matter”. According to this definition, the human civilization has been cloning matter during the earliest parts of history. Early farmers cut parts of plants and let them grow to become similar plants. The farmers also devised breeding techniques in order to reproduce plants with desirable characteristics. However, these methods proved to be ineffective until the late twentieth century, when scientists were able to manipulate plant DNA. The process has allowed researchers to create thousands of plants inexpensively (“Cloning” 1). Despite all the knowledge of cloning, the first animal clones were formed only one hundred years ago.

During the late 1800s, Hans Dreisch created the first cloned animals. His experiment involved the use of sea urchins, which have large embryos. Dreisch took the two-celled embryo of an urchin and vigorously shook the embryo in a beaker full of sea water. The embryo eventually split and each cell became a separate sea urchin.

In 1902, Hans Spemman used a single hair to separate the two-celled embryo of a salamander. He later removed a single cell from the sixteen-celled embryo. Both embryos eventually developed into identical salamanders. Later, Spemman proposed “what he called a ‘fantastical experiment’- to remove the genetic material from an adult cell, and use it to grow another adult”.

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There were no more major advances in cloning until November 1951, when a team of scientists in the United States cloned a frog embryo. The team used the “fantastical experiment” envisioned by Hans Spemman fifty years earlier to create the embryo. They removed the nucleus of a frog embryo cell and used it to replace the nucleus of an unfertilized frog egg. Eventually, the embryo began to grow and divide. This method is called nuclear transplant and is still in use today. Soon after the popular experiment, a plethora of frauds claimed to have cloned mammals. Because of these hoaxes, interest and funding in cloning began to drop. Scientists claimed that the cloning of mammals was impossible and cloning “returned to the realm of science-fiction” (“History of Cloning” 1-3). However, the birth of a sheep named Dolly would reignite “a firestorm of public and scientific interest” (Brem and Kuhholzer 57).

In Scotland, Ian Wilmut was called to create a sheep with a certain chemical in its milk. He chose to alter adult sheep cells and eventually, he began to clone them. One of Wilmut’s colleagues thought that the clone cells were in “incompatible stages of life”. Wilmut discovered that by starving the cells, they could be forced into “cellular hibernation”. Thus, the survival rate of the cloned cells increased. Using this process, Wilmut and his scientists created Dolly, the first cloned mammal. Dolly soon gained popularity throughout the world. Though scientists were impressed, they “demanded a better way”. The birth of Dolly and the demand for a “better way” has led to increasing research and controversy over cloning. Though cloning is currently facing opposition, other methods, such as the use of stem cells, might allow scientist to achieve a “new age of medicine” (“History of Cloning” 1-3).

Major Techniques

There are five major cloning techniques. The first technique is the use of blastomere separation. Scientists allow an embryo to form a mass of four cells. The outer coating of the embryo is removed and the remaining cells of the embryo, known as blastomeres, are separated. Each blastomere is placed in culture, where it forms an embryo with the identical genetic material of the original embryo. The resulting embryo is then implanted into a surrogate mother.

Another method is known as blastocyst division. Scientists “allow a fertilized egg to divide until it forms a mass of about thirty two to one hundred fifty cells, known as a blastocyst”. The blastocyst is then split into two and like in blastomere separation, placed in a proxy mother. The two halves eventually develop into identical twins (“Cloning” 3).

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

Brem, Gottfried and Birgit Kühholzer. “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.

"Cloning," Microsoft Encarta Online Encyclopedia 2003. http://encarta.msn.com/encnet/refpages/RefArticle.aspx?refid=761567589

1997-2003 Microsoft Corporation. 07/07/03.

“Cloning Fact Sheet.” Human Genome Project Information. http://www.ornl.gov/TechResources/Human_Genome/elsi/cloning.html. 07/07/03.

Dinnyés, András; 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.