World Library  
Flag as Inappropriate
Email this Article

Human cloning

Article Id: WHEBN0000014094
Reproduction Date:

Title: Human cloning  
Author: World Heritage Encyclopedia
Language: English
Subject: In the news/Candidates/April 2014, Colony (The X-Files), WikiProject Sociology/Cleanup listing, InterAcademy Panel, Zentradi
Collection: Biotechnology, Cloning
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Human cloning

Diagram of the ways to reprogram cells along with the development of humans.
Human cloning is the creation of a genetically identical copy of a human. The term is generally used to refer to artificial human cloning, which is the reproduction of human cells and tissue. It does not refer to the natural conception and delivery of identical twins. The possibility of human cloning has raised controversies. These ethical concerns have prompted several nations to pass laws regarding human cloning and its legality.

Two commonly discussed types of theoretical human cloning are: therapeutic cloning and reproductive cloning. Therapeutic cloning would involve cloning cells from a human for use in medicine and transplants, and is an active area of research, but is not in medical practice anywhere in the world, as of 2015. Two common methods of therapeutic cloning that are being researched are somatic-cell nuclear transfer and, more recently, pluripotent stem cell induction. Reproductive cloning would involve making an entire cloned human, instead of just specific cells or tissues.

Contents

  • History 1
  • Methods 2
    • Somatic cell nuclear transfer (SCNT) 2.1
    • Induced pluripotent stem cells (iPSCs) 2.2
    • Comparing SCNT to Reprogramming 2.3
  • Uses, actual and potential 3
  • Ethical implications 4
  • Current law 5
    • Australia 5.1
    • Canada 5.2
    • Colombia 5.3
    • European Union 5.4
    • India 5.5
    • Romania 5.6
    • Serbia 5.7
    • United Kingdom 5.8
    • United Nations 5.9
    • United States 5.10
  • In popular culture 6
  • References 7
  • Further reading 8
  • External links 9

History

Although the possibility of cloning humans had been the subject of speculation for much of the twentieth century, scientists and policy makers began to take the prospect seriously in the 1960s.

Nobel Prize-winning geneticist Joshua Lederberg advocated cloning and genetic engineering in an article in The American Naturalist in 1966 and again, the following year, in The Washington Post.[1] He sparked a debate with conservative bioethicist Leon Kass, who wrote at the time that "the programmed reproduction of man will, in fact, dehumanize him." Another Nobel Laureate, James D. Watson, publicized the potential and the perils of cloning in his Atlantic Monthly essay, "Moving Toward the Clonal Man", in 1971.[2]

With the cloning of a sheep known as Dolly in 1996 by somatic cell nuclear transfer (SCNT), the idea of human cloning became a hot debate topic.[3] Many nations outlawed it, while a few scientists promised to make a clone within the next few years. The first hybrid human clone was created in November 1998, by Advanced Cell Technology. It was created using SCNT - a nucleus was taken from a man's leg cell and inserted into a cow's egg from which the nucleus had been removed, and the hybrid cell was cultured, and developed into an embryo. The embryo was destroyed after 12 days.[4]

In 2004 and 2005, Hwang Woo-suk, a professor at Seoul National University, published two separate articles in the journal Science claiming to have successfully harvested pluripotent, embryonic stem cells from a cloned human blastocyst using somatic-cell nuclear transfer techniques. Hwang claimed to have created eleven different patent-specific stem cell lines. This would have been the first major breakthrough in human cloning.[5] However, in 2006 Science retracted both of his articles on clear evidence that much of his data from the experiments was fabricated.[6]

On January 2008, Dr. Andrew French and Samuel Wood of the biotechnology company Stemagen announced that they successfully created the first five mature human embryos using SCNT. In this case, each embryo was created by taking a nucleus from a skin cell (donated by Wood and a colleague) and inserting it into a human egg from which the nucleus had been removed. The embryos were developed only to the blastocyst stage, at which point they were studied in processes that destroyed them. Members of the lab said that their next set of experiments would aim to generate embryonic stem cell lines; these are the "holy grail" that would be useful for therapeutic or reproductive cloning.[7][8]

In 2011, scientists at the New York Stem Cell Foundation announced that they had succeeded in generating embyronic stem cell lines, but their process involved leaving the oocyte's nucleus in place, resulting in triploid cells, which would not be useful for cloning.[9][10][11]

In 2013, a group of scientists led by mitochondrial DNA inherited was identical.[9] A year later, a team led by Robert Lanza at Advanced Cell Technology reported that they had replicated Mitalipov's results and further demonstrated the effectiveness by cloning adult cells using SCNT.[3][12]

Methods

Somatic cell nuclear transfer (SCNT)

Diagram of SCNT Process

In somatic cell nuclear transfer ("SCNT"), the nucleus of a somatic cell is taken from a donor and transplanted into a host egg cell, which had its own genetic material removed previously, making it an enucleated egg. After the donor somatic cell genetic material is transferred into the host oocyte with a micropipette, the somatic cell genetic material is fused with the egg using an electric current. Once the two cells have fused, the new cell can be permitted to grow in a surrogate or artificially.[13] This is the process that was used to successfully clone Dolly the sheep (see section on History in this article).[3]

Induced pluripotent stem cells (iPSCs)

Overview of iPS cells

Creating induced pluripotent stem cells ("iPSCs") is a long and inefficient process. Pluripotency refers to a stem cell that has the potential to differentiate into any of the three germ layers: endoderm (interior stomach lining, gastrointestinal tract, the lungs), mesoderm (muscle, bone, blood, urogenital), or ectoderm (epidermal tissues and nervous system).[14] A specific set of genes, often called "reprogramming factors", are introduced into a specific adult cell type. These factors send signals in the mature cell that cause the cell to become a pluripotent stem cell. This process is highly studied and new techniques are being discovered frequently on how to better this induction process.

Depending on the method used, reprogramming of adult cells into iPSCs for implantation could have severe limitations in humans. If a virus is used as a reprogramming factor for the cell, cancer-causing genes called oncogenes may be activated. These cells would appear as rapidly dividing cancer cells that do not respond to the body's natural cell signaling process. However, in 2008 scientists discovered a technique that could remove the presence of these oncogenes after pluripotency induction, thereby increasing the potential use of iPSC in humans.[15]

Comparing SCNT to Reprogramming

Both the processes of SCNT and iPSCs have benefits and deficiencies. Historically, reprogramming methods were better studied than SCNT derived embryonic stem cells (ESCs).[9] However, more recent studies have put more emphasis on developing new procedures for SCNT-ESCs. The major advantage of SCNT over iPSCs at this time is the speed with which cells can be produced. iPSCs derivation takes several months while SCNT would take a much shorter time, which could be important for medical applications. New studies are working to improve the process of iPSC in terms of both speed and efficiency with the discovery of new reprogramming factors in oocytes. Another advantage SCNT could have over iPSCs is its potential to treat mitochondrial disease, as it utilizes a donor oocyte.[9] No other advantages are known at this time in using stem cells derived from one method over stem cells derived from the other.[16]

Uses, actual and potential

Stem cell treatments

Work on cloning techniques has advanced our basic understanding of developmental biology in humans. Observing human pluripotent stem cells grown in culture provides great insight into human embryo development, which otherwise cannot be seen. Scientists are now able to better define steps of early human development. Studying signal transduction along with genetic manipulation within the early human embryo has the potential to provide answers to many developmental diseases and defects. Many human-specific signaling pathways have been discovered by studying human embryonic stem cells. Studying developmental pathways in humans has given developmental biologists more evidence toward the hypothesis that developmental pathways are conserved throughout species.[17]

iPSCs and cells created by SCNT are useful for research into the causes of disease, and as model systems used in drug discovery.[18][19]

Cells produced with SCNT, or iPSCs could eventually be used in

  • "Variations and voids: the regulation of human cloning around the world" academic article by S. Pattinson & T. Caulfield
  • Moving Toward the Clonal Man
  • Should We Really Fear Reproductive Human Cloning
  • United Nation declares law against cloning.
  • General Assembly Adopts United Nations Declaration on Human Cloning By Vote of 84-34-37
  • Cloning Fact Sheet
  • How Human Cloning Will Work

External links

  • Araujo, Robert John, "The UN Declaration on Human Cloning: a survey and assessment of the debate," 7 The National Catholic Bioethics Quarterly 129 - 149 (2007).
  • Oregon Health & Science University. "Human skin cells converted into embryonic stem cells: First time human stem cells have been produced via nuclear transfer." ScienceDaily. ScienceDaily, 15 May 2013. [1].

Further reading

  1. ^
  2. ^ Watson, James. "Moving Toward a Clonal Man: Is This What We Want?" The Atlantic Monthly (1971).
  3. ^ a b c
  4. ^
  5. ^ Fischbak, Ruth L., John D. Loike, Janet Mindes, and Columbia Center for New Media Teaching & Learning. The Cloning Scandal of Hwang Woo-Suk, part of the online course, Stem Cells: Biology, Ethics, and Applications
  6. ^
  7. ^ Rick Weiss for the Washington Post January 18, 2008 Mature Human Embryos Created From Adult Skin Cells
  8. ^
  9. ^ a b c d
  10. ^
  11. ^
  12. ^
  13. ^
  14. ^
  15. ^
  16. ^
  17. ^
  18. ^
  19. ^
  20. ^
  21. ^ Bone Marrow Transplantation and Peripheral Blood Stem Cell Transplantation In National Cancer Institute Fact Sheet web site. Bethesda, MD: National Institutes of Health, U.S. Department of Health and Human Services, 2010. Cited August 24, 2010
  22. ^ Cell Basics: What are the potential uses of human stem cells and the obstacles that must be overcome before these potential uses will be realized?. In Stem Cell Information World Wide Web site. Bethesda, MD: National Institutes of Health, U.S. Department of Health and Human Services, 2009. cited Sunday, April 26, 2009
  23. ^
  24. ^
  25. ^
  26. ^
  27. ^
  28. ^
  29. ^
  30. ^ Staff, Times Higher Education. August 10, 2001 In the news: Antinori and Zavos
  31. ^
  32. ^
  33. ^
  34. ^
  35. ^
  36. ^
  37. ^ Bob Sullivan, Technology correspondent for MSNBC. November 262003 Religions reveal little consensus on cloning - Health - Special Reports - Beyond Dolly: Human Cloning
  38. ^ William Sims Bainbridge, Ph.D. Religious Opposition to Cloning Journal of Evolution and Technology - Vol. 13 - October 2003
  39. ^ Prohibition of Human Cloning for Reproduction Act 2002 National Health and Medical Research Council, 12 June 2007
  40. ^ (April 2014) Research cloning - Legal Aspects Deutches Referenzzentrum fur Ethik in den Biowissenschaften, Retrieved 19 April 2014
  41. ^
  42. ^ "Overview of World Human Cloning Policies." Connexions - Sharing Knowledge and Building Communities. N.p., n.d. Web. 29 Nov. 2011. http://cnx.org/content/m14834/latest/
  43. ^ "Canada Bans Human Cloning - Research and Read Books, Journals, Articles at Questia Online Library." Questia - The Online Library of Books and Journals. N.p., n.d. Web. 7 Dec. 2011. http://www.questia.com/googleScholar.qst?docId=5006805131.
  44. ^ "Canada Closes Door on Cloning ." Wired.com . N.p., n.d. Web. 29 Nov. 2011.
  45. ^ "Regulating and treating conception problems - Health - CBC News." CBC.ca - Canadian News Sports Entertainment Kids Docs Radio TV. N.p., n.d. Web. 7 Dec. 2011. http://www.cbc.ca/news/health/story/2009/02/05/f-reprotech.html.
  46. ^ "Ley 599 de 2000 (Julio 24) Por la cual se expide el Código Penal." http://www.alcaldiabogota.gov.co/sisjur/normas/Norma1.jsp?i=6388
  47. ^ Treaty of Lisbon (2007/C 306/01) Article 6 (1)
  48. ^
  49. ^
  50. ^
  51. ^
  52. ^ Text of the Human Fertilisation and Embryology (Research Purposes) Regulations 2001 (No. 188) as originally enacted or made within the United Kingdom, from the UK Statute Law Database
  53. ^
  54. ^
  55. ^
  56. ^
  57. ^
  58. ^ "United Nations Declaration on Human Cloning". Bio Etica Web. March 16, 2005.
  59. ^
  60. ^
  61. ^
  62. ^
  63. ^
  64. ^ Never Let Me Go on IMDB
  65. ^ The Island on IMDB
  66. ^ Star Wars: The Clone Wars on IMDB
  67. ^ Orphan Black on IMDB

References

Orphan Black, a sci-fi/drama television series explores the ethical issues, and biological advantages/disadvantages of human cloning through a fictional scientific study on the behavioral adaptation of clones in society.[67]

The use of human cloning for military purposes has also been explored in several works. Star Wars portrays human cloning in Clone Wars,[66] Star Wars Episode II: Attack of the Clones and Star Wars Episode III: Revenge of the Sith, in the form of the Grand Army of the Republic, an army of cloned soldiers.

A recurring sub-theme of cloning fiction is the use of clones as a supply of

The reduction in the value of the individual human life in a resource-optimized clone-based society is examined in the 1967 novel Logan's Run, and the later movie.

Science fiction has used cloning, most commonly and specifically human cloning, due to the fact that it brings up controversial questions of identity.[62][63] In Aldous Huxley’s Brave New World (1932), human cloning is a major plot device that not only drives the story but also makes the reader think critically about what identity means; this concept was re-examined fifty years later in C. J. Cherryh’s novels Forty Thousand in Gehenna (1983) and Cyteen (1988). Kazuo Ishiguro's 2005 novel Never Let Me Go centers on human clones and considers the ethics of the practice.

In popular culture

In 1998, 2001, 2004, and 2007, the United States House of Representatives voted whether to ban all human cloning, both reproductive and therapeutic. Each time, divisions in the Senate over therapeutic cloning prevented either competing proposal (a ban on both forms or reproductive cloning only) from passing. On March 10, 2010 a bill (HR 4808) was introduced with a section banning federal funding for human cloning.[60] Such a law, if passed, would not prevent research from occurring in private institutions (such as universities) that have both private and federal funding. There are currently no federal laws in the United States which ban cloning completely, and any such laws would raise difficult constitutional questions similar to the issues raised by abortion. Thirteen American states (Arkansas, California, Connecticut, Iowa, Indiana, Massachusetts, Maryland, Michigan, North Dakota, New Jersey, Rhode Island, South Dakota, and Virginia) ban reproductive cloning and three states (Arizona, Maryland, and Missouri) prohibit use of public funds for such activities.[61]

United States

On December 13, 2001, the United Nations General Assembly began elaborating an international convention against the reproductive cloning of humans. A broad coalition of States, including Spain, Italy, the Philippines, the United States, Costa Rica and the Holy See sought to extend the debate to ban all forms of human cloning, noting that, in their view, therapeutic human cloning violates human dignity. Costa Rica proposed the adoption of an international convention to ban all forms of human cloning. Unable to reach a consensus on a binding convention, in March 2005 a non-binding United Nations Declaration on Human Cloning, calling for the ban of all forms of human cloning contrary to human dignity, was adopted.[58][59]

United Nations

The first license was granted on August 11, 2004 to researchers at the University of Newcastle to allow them to investigate treatments for diabetes, Parkinson's disease and Alzheimer's disease.[56] The Human Fertilisation and Embryology Act 2008, a major review of fertility legislation, repealed the 2001 Cloning Act by making amendments of similar effect to the 1990 Act. The 2008 Act also allows experiments on hybrid human-animal embryos.[57]

On January 14, 2001 the British government passed The Human Fertilisation and Embryology (Research Purposes) Regulations 2001[52] to amend the Human Fertilisation and Embryology Act 1990 by extending allowable reasons for embryo research to permit research around stem cells and cell nuclear replacement, thus allowing therapeutic cloning. However, on November 15, 2001, a pro-life group won a High Court legal challenge, which struck down the regulation and effectively left all forms of cloning unregulated in the UK. Their hope was that Parliament would fill this gap by passing prohibitive legislation.[53][54] Parliament was quick to pass the Human Reproductive Cloning Act 2001 which explicitly prohibited reproductive cloning. The remaining gap with regard to therapeutic cloning was closed when the appeals courts reversed the previous decision of the High Court.[55]

United Kingdom

Human cloning is explicitly prohibited in Article 24, "Right to Life" of the 2006 Constitution of Serbia.[51]

Serbia

Cloning a human is prohibited in Romania.

Romania

India does not have specific law regarding cloning but has guidelines prohibiting whole human cloning or reproductive cloning. India allows therapeutic cloning and the use of embryonic stem cells for research proposes.[49][50]

India

The European Convention on Human Rights and Biomedicine prohibits human cloning in one of its additional protocols, but this protocol has been ratified only by Greece, Spain and Portugal. The Charter of Fundamental Rights of the European Union explicitly prohibits reproductive human cloning. The charter is legally binding for the institutions of the European Union under the Treaty of Lisbon and for member states of the Union implementing EU law.,[47][48]

European Union

Human cloning is prohibited in Article 133 of the Colombian Penal Code.[46]

Colombia

There have been consistent calls in Canada to ban human reproductive cloning since the 1993 Report of the Royal Commission on New Reproductive Technologies. Polls have indicated that an overwhelming majority of Canadians oppose human reproductive cloning, though the regulation of human cloning continues to be a significant national and international policy issue. The notion of "human dignity" is commonly used to justify cloning laws. The basis for this justification is that reproductive human cloning necessarily infringes notions of human dignity.[42][43][44][45]

Canadian law prohibits the following: cloning humans, cloning stem cells, growing human embryos for research purposes, and buying or selling of embryos, sperm, eggs or other human reproductive material.[41] It also bans making changes to human DNA that would pass from one generation to the next, including use of animal DNA in humans. Surrogate mothers are legally allowed, as is donation of sperm or eggs for reproductive purposes. Human embryos and stem cells are also permitted to be donated for research.

Canada

Australia has prohibited human cloning,[39] though as of December 2006, a bill legalizing therapeutic cloning and the creation of human embryos for stem cell research passed the House of Representatives. Within certain regulatory limits, and subject to the effect of state legislation, therapeutic cloning is now legal in some parts of Australia.[40]

Australia

Current law

Religious groups are divided, with some opposing the technology as usurping God's (in monotheistic traditions) place and, to the extent embryos are used, destroying a human life; others support therapeutic cloning's potential life-saving benefits.[37][38]

[36][35] and have concerns about how cloned individuals could integrate with families and with society at large.[34][33] Some opponents of reproductive cloning have concerns that technology is not yet developed enough to be safe - for example, the position of the

Opposition to therapeutic cloning mainly centers around the status of embyronic stem cells, which has connections with the abortion debate.[31]

Advocates support development of therapeutic cloning in order to generate tissues and whole organs to treat patients who otherwise cannot obtain transplants,[27] to avoid the need for immunosuppressive drugs,[28] and to stave off the effects of aging.[29] Advocates for reproductive cloning believe that parents who cannot otherwise procreate should have access to the technology.[30]

In bioethics, the ethics of cloning refers to a variety of ethical positions regarding the practice and possibilities of cloning, especially human cloning. While many of these views are religious in origin, the questions raised by cloning are faced by secular perspectives as well. Human therapeutic and reproductive cloning are not commercially used; animals are currently cloned in laboratories and in livestock production.

Ethical implications

[26] In current research, human pluripotent stem cells have been promised as a reliable source for generating human neurons, showing the potential for regenerative medicine in brain and neural injuries.[25] For instance, a person with liver disease could potentially have a new liver grown using their same genetic material and transplanted to remove the damaged liver.[24]

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.