Cloning

Article By:

Wolf, Don P. Division of Reproductive Sciences, Oregon National Primate Center, Beaverton, Oregon.

White, Kenneth L. Department of Animal, Dairy, and Veterinary Sciences, Center for Integrated Biosystems, Utah State University, Logan, Utah.

Aston, Kenneth I. Department of Animal, Dairy, and Veterinary Sciences, Center for Integrated Biosystems, Utah State University, Logan, Utah.

Sessions, Benjamin R. Department of Animal, Dairy, and Veterinary Sciences, Center for Integrated Biosystems, Utah State University, Logan, Utah.

Last reviewed:April 2021

DOI:https://doi.org/10.1036/1097-8542.801190

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• Cloning, published June 2014:Download PDF Get Adobe Acrobat Reader

The asexual creation of a genetic copy of a biological entity, such as a cell, gene, tissue, or organism. The process of cloning is a capability possessed by plants, but not by most animals (Fig. 1). Plants generate genetic copies spontaneously, and the rooting of "cuttings" is widely used by horticulturists to propagate millions of clones annually. In animals, only some lower invertebrates can be cloned by "cutting"; for example, when earthworms are bisected, they will regenerate the missing half, resulting in two whole, genetically identical individuals. However, asexual reproduction and cloning do not normally occur in vertebrates, except for the special case of identical twinning. This is despite the fact that individual cells, called blastomeres, within the very early embryo are totipotent; that is, each is capable, if evaluated on its own, of developing into a viable term pregnancy and infant. See also: Animal reproduction; Plant propagation

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