Animal Cloning

clone

clone, group of organisms, all of which are descended from a single individual through asexual reproduction, as in a pure cell culture of bacteria. Except for changes in the hereditary material that come about by mutation, all members of a clone are genetically identical. In 1962 John Gurdon was the first to clone an animal when he transferred cell nuclei from adult frog intestinal cells and injected them into egg cells from which the nucleus had been removed; the eggs then developed into tadpoles. Laboratory experiments in in vitro fertilization of human eggs led in 1993 to the "cloning" of human embryos by dividing such fertilized eggs at a very early stage of development, but this technique actually produces a twin rather than a clone. In a true mammalian clone (as in Gurdon's frog clone) the nucleus from a body cell of an animal is inserted into an egg, which then develops into an individual that is genetically identical to the original animal.

Later experiments in cloning resulted in the development of a sheep from a cell of an adult ewe (in Scotland, in 1996), and since then rodents, cattle, swine, and other animals have also been cloned from adult animals. Despite these trumpeted successes, producing cloned mammals is enormously difficult, with most attempts ending in failure; cloning succeeds 4% or less of the time in the species that have been successfully cloned. In addition, some studies have indicated that cloned animals are less healthy than normally reproduced animals.

In 2001 researchers in Massachusetts announced that they were trying to clone humans in an attempt to extract stem cells. The National Academy of Sciences, while supporting (2001) such so-called therapeutic or research cloning, has opposed (2002) the cloning of humans for reproductive purposes, deeming it unsafe, but many ethicists, religious and political leaders, and others have called for banning human cloning for any purpose. South Korean scientists announced in 2004 that they had cloned 30 human embryos, but an investigation in 2005 determined that the data had been fabricated. In 2013 scientists at Oregon Health and Science Univ. reported that they had created embryonic stem cells using genetic material from human skin cells and donated eggs; the technique used to create the embryo, however, would not result in a viable human clone.

See G. Kolata, Clone (1997).

The Columbia Encyclopedia, 6th ed. Copyright© 2013, The Columbia University Press.

Selected full-text books and articles on this topic

The Cloning Sourcebook
Arlene Judith Klotzko.
Oxford University Press, 2001
Librarian’s tip: Chap. 14 "Cloning Humans and Cloning Animals"
The Hope, Hype & Reality of Genetic Engineering: Remarkable Stories from Agriculture, Industry, Medicine, and the Environment
John C. Avise.
Oxford University Press, 2004
Librarian’s tip: Chap. 5 "Genetic Engineering in the Barnyard"
Biotechnology and Communication: The Meta-Technologies of Information
Sandra Braman.
Lawrence Erlbaum Associates, 2004
Librarian’s tip: "Brave New Barnyard: The Advent of Animal Cloning" begins on p. 199
Creating Fido's Twin: Can Pet Cloning Be Ethically Justified?
Fiester, Autumn.
The Hastings Center Report, Vol. 35, No. 4, July-August 2005
Evolution's Rainbow: Diversity, Gender, and Sexuality in Nature and People
Joan Roughgarden.
University of California Press, 2004
Librarian’s tip: "Cloning Whole Organisms" begins on p. 307
Ethical Issues in Human Cloning: Cross-Disciplinary Perspectives
Michael C. Brannigan.
Seven Bridges Press, 2001
Librarian’s tip: "Dolly's Fashion and Louis's Passion: Ruminations on the Downfall of a King and the Cloning of a Sheep" begins on p. 34
Genetic Nature/Culture: Anthropology and Science beyond the Two-Culture Divide
Alan H. Goodman; Deborah Heath; M. Susan Lindee.
University of California Press, 2003
Librarian’s tip: Chap. 5 "Kinship, Genes, and Cloning: Life after Dolly"
Key Issues in Bioethics: A Guide for Teachers
Ralph Levinson; Michael J. Reiss.
RoutledgeFalmer, 2003
Librarian’s tip: Part II "Cloning"
The "New" Genetics and Mammalian Cloning in Environmental Health Research
Iannaccone, Philip M.
Environmental Health Perspectives, Vol. 108, No. 10, October 2000
Cloning Red Herrings: Why Concerns about Human-Animal Experiments Are Overblown
Longtin, David; Kraemer, Duane C.
Policy Review, February 2002
Thylacine: The Tragic Tale of the Tasmanian Tiger
David Owen.
Allen & Unwin, 2003
Librarian’s tip: Chap. 14 "Beating a Seventy-Year Hiccup: Cloning"
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