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”.
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).