Therapeutic Cloning

Therapeutic Cloning http://www.duke.edu/web/pps114/project/10/Stem_Cell_Cartoon.jpg Jeffrey Cho AP Biology Period 3 / 4 Mrs. McCarron

History of Cloning • 1938 Dr. Hans Spemann (Germany) proposes an experiment to remove the nucleus from an unfertilized egg and replace it with the nucleus from a differentiated cell. • 1953 Structure of DNA discovered by Watson and Crick. • 1973 First successful gene splicing by Paul Berg and Stanley N. Cohen. • 1996 Dr. Ian Wilmut clones the world's the first sheep, who he names Dolly, from somatic adult cells. • 1997 Dr. Ian Wilmut and Dr. Keith Campbell (U.K.) create the first sheep, named Polly, with a human gene in every cell of its body. • 1999 An experiment to clone calves from frozen cells taken from a Japanese bull is successful and proves that cells can be stored for later cloning. • 2000 Japanese scientists clone a baby bull from a bull that was a clone itself, making it the first case of re-cloning. • 2001 President Bush limits federally funded human embryonic stem cell research to stem cell lines that have already been created. • 2001 . The British Parliament rules that embryonic stem cell research can occur using government funding. Human embryos can be created for therapeutic cloning prior to brain and nervous system development (14 days). • 2002 California becomes the first U.S. state to approve a law legalizing the therapeutic cloning of embryos. • 2003 President Bush declares that all human cloning should be banned during his State of the Union Address • 2003 U.S. House of Representatives passes the Human Cloning Prohibition Act, which bans both reproductive and therapeutic cloning. • 2003 Britain becomes the first country to issue research licenses for human embryonic cloning to create stem cells. (therapeutic only).

Background Information • Cloning is the process of producing individuals that are genetically identical. • Cloning occurs in nature, seen when organisms such as bacteria, insects, and plants reproduce asexually. • Even in organisms that reproduce sexually, cloning can occur. i.e identical twins.

Background Information • Three types of Cloning • Recombinant DNA Technology or DNA Cloning • DNA fragment is inserted and replicated by a bacterial plasmid. • Reproductive Cloning • Generate an organism that has the same DNA as another animal. Example: Dolly • Therapeutic Cloning • Stem cells that can be used to study human development and to treat disease are harvested from a blastocyst. http://wpcontent.answers.com/wikipedia/en/thumb/0/01/Recombinant_formation_of_plasmids.svg/280px-Recombinant_formation_of_plasmids.svg.png http://img.timeinc.net/time/daily/2008/0811/dolly_sheep_1120.jpg http://library.thinkquest.org/06aug/01611/graphics/technicalities-cloning/stemcell.png

Procedure Eggs are removed from the ovary of females and the nucleus is removed using a needle that is less than 2/10,000th of an inch wide. DNA, usually from skin cells, is extracted and inserted into the ovum. An electrical shock is applied to stimulate cell division. The pre-embryo is allowed to divide for 5-14 days, after which, stem cells are extracted resulting in the death of the blastocyst. The stem cells are encouraged to grow into specific organs which are then transferred to patients. Scientists have been able to differentiate stem cells into most of the 220 cell types in the human body. 5 Day Old Blastocyst http://www.brown.edu/Courses/BI0032/gentherp/earlyIE1.htm

Reproductive vs Therapeutic Cloning Process http://content.nejm.org/content/vol351/issue27/images/large/02f1.jpeg

Pros • Therapeutic cloning will allow for the production of specific organs that are 100% compatible with the patient in need of an organ transplant. • Immunosuppressive drugs needed to prevent organ rejection weaken the immune system and may cause hypertension, dyslipidemia, hyperglycemia, peptic ulcers, liver, and kidney injury. Medication does not always prevent organ rejection. • Therapeutic cloning eliminates the possibility of organ rejections as well as eliminates the need for dangerous immunosuppressant drugs. • Additionally, individuals donating organs would not have to inconvenienced by pain or a shortened life span in order to donate the organ. Families of deceased doners do not have to deal with the trauma of having an “incomplete” loved one.

Pros • Therapeutic cloning can also be used to treat a wide range of diseases and disorders such as diabetes and Parkinson’s disease. • Invasive surgery will not always necessary as therapeutic cloning will be able to repair damaged organs. • The molecular causes of disease can be discovered by studying embryonic stem cell lines from cloned embryos of organisms with a particular disease.

Cons • Pro-life supporters believe that life begins at conception and that the destruction of the embryo to extract the stem cells is akin to murder. • Pro-lifers do not believe in manufacturing life with the intention of eventually destroying it. • Stem cells have sometimes mutated, and have been rejected by the recipient's body. • In some cases, therapeutic cloning experiments on animals have produced tumors. • Female egg cells are needed for therapeutic cloning and currently, it takes about 100 eggs for a treatment to be successful. Removing eggs is costly and may result in injury to the female.

Opinion • I believe that therapeutic cloning is extremely beneficial and research should be supported and continued. • Lives can be saved through transplants and further research could merit cures to diseases such as diabetes and Parkinson’s disease. • The blastocyst is simply a bunch of cells and laws are in place to prevent the use of blastocysts that have been developing for more than 14 days, at which point they develop a nervous system. Though the cells die, no pain is felt. • Though the process of therapeutic cloning is similar to reproductive cloning, a complete organism does not develop. So fear of creating humans for spare parts is misplaced.

Opinion • An average of 18 people die each day from the lack of available organs for transplant. • Every 11 minutes another name is added to the waiting list. • More than 1 million people need whole eye and cornea transplants to save their life or significantly improve it. Number of People on the Waiting List In the United States ORGAN DONATION IN 2009 http://www.donatelifeny.org/organ/2009_unitedstates_1.html

Opinion • There are concerns about the lack of an egg supply however research into the use of non-human eggs is already underway. • People are upset that mutations/tumors have developed however, like everything, it takes time to perfect the process. • Current statistics about the percentage of people that support or disapprove of cloning are not accurate as they are conducted by independent companies with their own specific agendas. For example one company stated that 70% of the public supported human embryonic stem cell research while another study conducted by another group one month later stated that 70% of the public opposed stem cell research. • What is known is that far more people in the US disapprove of cloning than those in countries like the UK. I believe that despite what occurs in the United States, therapeutic cloning research will continue in countries such as China, the UK, perhaps Canada where the issue is less controversial.

Bibliography • http://www.medterms.com/script/main/art.asp?articlekey=18428 • http://www.ehow.com/about_5683512_medical-benefits-therapeutic-cloning.html • http://www.infoplease.com/ipa/A0193002.html • http://www.garlandscience.com/textbooks/cbl/stemcell/corematerials/timeline.html • http://www.geneticsandsociety.org/section.php?id=54 • http://www.donatelifeny.org/organ/o_statistics_overview.html

Therapeutic Cloning