Image of John Gurdon (Nuclear Transfer: Bringing in the Clones) http://www.pnas.org/site/misc/images/gurdon.jpg
Image of John Gurdon (Nuclear Transfer: Bringing in the Clones) http://www.pnas.org/site/misc/images/gurdon.jpg

Sir John Bertrand Gurdon



The Definitions of...
Cloning: Cloning is the production of identical multiple offspring.
Clone: A clone is an animal who is genetically identical to its donor parent.

Biography: Sir John Bertrand Gurdon, born the second of October 1933 in the southern part of England, is known as the godfather of cloning. At a younger age, his parents were very supportive of his education and sent him to private school. Although his father encouraged him to enroll in the army or to study business, his mother was the one who urged him into the science field. His was later told by the family doctor that a career in the army would not be possible due to his case of bronchitis. He studied the Classics after being told, at the age of fifteen, that it would be unwise for him to continue to study sciences. His professor had stated that he was the worst student he had ever taught in Biology. Gurdon then studied zoology at Oxford University, and only was accepted in if he agreed to study science rather than the classics of Latin and Greek. He later decided to go for his PhD in embryology under the direction of Michael Fischberg. After hard work, Gurdon stumbled upon his most famous discovery, which can be read about below. Gurdon is still alive today and is currently an Emeritus Professor in the Zoology Department of the Gurdon Institute.

Prior Knowledge: As stated above, Sir John Bertrand Gurdon studied the Classics of Latin and Greek at Eton before moving on to Oxford University, where he studied sciences. He got his PhD in embryology at Oxford University under the direction of Michael Fischberg. Fischberg influenced Gurdon in a number of ways. Fischberg recommended that Gurdon do his PhD dissertation about the nuclear transplantation in Xenopus laevis, also known as South African clawed frogs. Another contributing factor that led Gordon to choose the South African clawed frogs is because one can obtain eggs from them at any time of the year if you inject them with mammalian hormone. Other frogs lay eggs only one or two months out of the year. The Xenopus laevis also reaches sexual maturity after only six to twelve months, where other frogs take about four years to reach sexual maturity. Gurdon also chose a tadpole intestinal cell because of a tissue, called endoderm, which has very large cells that were convenient to work with. Endoderm cells go on to form tadpole intestinal cells, and along with being easy to work with, was also a continuously dividing cell type. Gurdon
began his experiments by repeating the nuclear transplantation steps of cell biologists of Briggs and King, who became the first scientists to transplant the nucleus from an early stage cell into an egg with successful results. Although every attempt to continue this path by Briggs and King failed, Gurdon used their reasearch and was inspired to conduct an experiment of his own. After awhile, Fischberg also pushed Gurdon to do ‘something completely different’. Gurdon’s experiments and the decisions that he made were a direct result of his prior knowledge of sciences, accumulated at Eton and Oxford, and his influences, which included Michael Fischberg.
Image of the Transferring of a Nucleus (The Great Beyond) http://blogs.nature.com/news/thegreatbeyond/2009/09/stem_cell_pioneers_take_home_l.html
Image of the Transferring of a Nucleus (The Great Beyond) http://blogs.nature.com/news/thegreatbeyond/2009/09/stem_cell_pioneers_take_home_l.html


Description of Experiment: In 1962, John Gurdon successfully cloned a frog caleed the Xenopus using the nucleus of the somatic cell, or one that takes part in the formation of the body, from the intestinal lining of tadpoles. Before him, the only frogs that had been experimented on were the Rana Pipiens, but the American frogs had some advantages. Whenever mammalian hormone was injected into the frog, it would lay eggs, unlike the Rana which only would during certain months of the year. It also reaches sexual maturity quicker than other kinds of frogs. For his experiments, he took cells that were modified from his exp
Gurdon's Ultraviolet Microscope (Procedure of Cloning) http://robby.nstemp.com/photo2.html
Gurdon's Ultraviolet Microscope (Procedure of Cloning) http://robby.nstemp.com/photo2.html
eriments, or differentiated from cells such as skin cells, from tadpoles. Then, he exposed the frog egg to ultraviolet rays, from a ultraviolet microscope, destroying the nucleus. From the intestinal cell he removed the nucleus and implanted it in the egg without a nucleus. Gurdon began cloning experiments using cells—specifically, cells from the intestinal lining of tadpoles. Then the egg developed into a tadpole with DNA identical to the one taken from. The only problem with his experiment was that the tadpoles never lived to adulthood. Scientists believed this was because some of the cells he used were never differentiated. Later in his work, however, Gurdon produced sexually mature adult frogs from eggs using almost the exact system; one in which genetically marked nuclei had been transplanted from differential tadpole cells.external image moz-screenshot.png
Gurdon's Experiment (How Cloning Works) http://images.google.com/imgres?imgurl=http://static.howstuffworks.com/gif/cloning-frog.gif&imgrefurl=http://science.howstuffworks.com/genetic-science/cloning.htm/printable&usg=__VbVIuqF3kuTxEQfoNzto3EQhk5U=&h=282&w=396&sz=11&hl=en&start=1&um=1&tbnid=HRv5EpcRM-dB_M:&tbnh=88&tbnw=124&prev=/images%3Fq%3DJohn%2BGurdon%2527s%2Bexperiment%26hl%3Den%26rls%3Dig%26sa%3DN%26um%3D1
Gurdon's Experiment (How Cloning Works) http://images.google.com/imgres?imgurl=http://static.howstuffworks.com/gif/cloning-frog.gif&imgrefurl=http://science.howstuffworks.com/genetic-science/cloning.htm/printable&usg=__VbVIuqF3kuTxEQfoNzto3EQhk5U=&h=282&w=396&sz=11&hl=en&start=1&um=1&tbnid=HRv5EpcRM-dB_M:&tbnh=88&tbnw=124&prev=/images%3Fq%3DJohn%2BGurdon%2527s%2Bexperiment%26hl%3Den%26rls%3Dig%26sa%3DN%26um%3D1

Results of Experiment: John Gurdon cloned tadpoles. The question that had been looming over cell biologists before his experiments was whether or not the cells of an adult organism were genetically identical to the fertilized egg from which they were derived. He answered this question through his research with a yes. Gurdon explained in an interview that the most efficient way to clone is nuclear transfer, yet there is still much to be learned from it. Gurdon's experiments also proved that with development, genetic material does not undergo change that cannot be reversed. His results were successful and his discoveries will and have impacted experiments for further generations.

Impact of John Gurdon's Experiments: John Gurdon’s experiments have impacted the science world already and “electrified the science community”. 1963, the British biologist J.B.S. Haldane came up with the term for what Gurdon accomplished in his studies. The word “clone”, although several scientists had described and even completed this process, had never been used to describe what Gurdon had invented. This term has been used ever since. On July 5, 1996, Dolly the sheep, the first organism ever to be cloned from adult cells, was born based off of Gurdon’s efforts. Ian Wilmut and Keith Campbell, researchers in Scotland created Dolly using a technique similar to that of Gurdon’s using differentiated nuclear cells. Many people are against coning because they believe it is against morals. There are plenty of reasons against cloning, whether it be scientific, religious, or practicality objections. Many people do not think cloning is a good idea because there is a very high chance that it will not work because the science is not precise enough to prevent failure. For example, it took the cloning of Dolly several times before it worked and there is a high percentage of mutated genes as well. Many people do not believe in cloning, especially that of humans because mostly clones are just used for “parts”, because it is against religious and moral rights. People believe that human life is precious in God’s eyes and everyone deserves to live a valuable life. One of the many benefits of cloning is that it helps increase the numbers of animals in certain endangered species. The first endangered species that was cloned was a baby bull gaur (a large wild ox from India and southeast Asia) named Noah. The cloning of the animal proved that cloning can be done to help save wild animals. Also, clones can be used for someone who needs body parts to get what they need. In the future, because of Gurdon’s experiments, many controversial and exciting new discoveries and technologies will ensue.

Extra Information:
For more information on cloning, and specifically cloning Dolly the Sheep, watch this video: How they cloned Dolly the Sheep


Sources:
(2nd Rodney Porter Memorial Lecture) http://www.bioch.ox.ac.uk/glycob/rodney_porter_lectures/1999/gurdon.html)
(John Gurdon, British Developmental Biologist) http://www.brighthub.com/science/genetics/articles/21417.aspx
(Gurdon Institute) http://www.gurdon.cam.ac.uk/gurdon.html
(John Gurdon, British Developmental Biologist) http://www.brighthub.com/science/genetics/articles/21417.aspx?p=2
(The Birth of Cloning: An Interview with John Gurdon) http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2615171/
(Sir John Gurdon: Godfather of Cloning) http://jcb.rupress.org/cgi/content/full/181/2/178
(1962: Did Gurdon Clone Frogs?) http://library.thinkquest.org/24355/data/details/1962.html
(Agruments Against Cloning) http://www.allaboutpopularissues.org/arguments-against-cloning-faq.htm

(Conversations with Sir John Gurdon) http://globetrotter.berkeley.edu/people6/Gurdon/gurdon-con1.html
(You Tube - How they cloned Dolly the Sheep) http://www.youtube.com/watch?v=39BbcZVCx8I

By: Nora and Sarah