Artificial selection

Artificial selection is the intentional breeding for certain traits, or combinations of traits, over others, and is synonymous with "Selective breeding". It was originally defined by Charles Darwin in contrast to the process of natural selection, in which the differential reproduction of organisms with certain traits is attributed to improved survival and/or reproductive ability ("Darwinian fitness") in the natural habitat of the organism. Artificial selection that produces an undesirable outcome from a human perspective is sometimes called "negative selection" (but note that this term has a better-established meaning as a type of natural selection; see negative selection). Artificial selection can also be unintentional; it is thought that domestication of crops by early humans was largely unintentional. [ [http://www.botany.wisc.edu/courses/botany_940/powerpoints/ArtificialSelection.ppt Artificial Selection powerpoint, University of Wisconsin-Madison] ]

Historical development

Charles Darwin coined the term as an illustration of his proposed wider process of natural selection. Darwin noted that many domesticated animals and plants had special properties that were developed by intentionally encouraging the breeding potential of individuals who both possessed desirable characteristics, and discouraging the breeding of individuals who had less desirable characteristics.

Contrast to natural selection

It should be emphasized that there is no real difference in the genetic processes underlying artificial and natural selection, and that the concept of artificial selection was first introduced as an illustration of the wider process of natural selection. The selection process is termed "artificial" when human preferences or influences have a significant effect on the evolution of a particular population or species. Indeed, many evolutionary biologists view domestication as a type of natural selection and adaptive change that occurs as organisms are brought under the control of human beings.

Laboratory usage

The deliberate exploitation of selective power has become common in experimental biology, particularly in microbiology and genetics. In a ubiquitous laboratory technique in genetic engineering, genes are introduced into cells in cell culture, usually bacteria, on a small circular DNA molecule called a plasmid in a process called transfection. The gene of interest is accompanied on the plasmid by a reporter gene, or "selectable marker", which encodes a specific trait such as antibiotic resistance or ability to grow in high salt concentrations. The cells can then be cultured in an environment that would kill normal cells, but is hospitable to those that have taken up and expressed the genes on the plasmid. In this way expression of the reporter gene serves as a signal that the gene of interest is also being expressed in the cells.

Another technique used in drug development uses an iterative selective process called "in vitro" selection to evolve aptamers, or nucleic acid fragments capable of binding specific organic compounds with high binding affinity.

Studies in evolutionary physiology, behavioral genetics, and other areas of organismal biology have also made use of deliberate artificial selection, though longer generation times and greater difficulty in breeding can make such projects challenging in vertebrates.Swallow JG, Garland T. (2005). Selection experiments as a tool in evolutionary and comparative physiology: insights into complex traits—an introduction to the symposium. "Integr Comp Biol", 45:387–390. [http://biology.ucr.edu/people/faculty/Garland/SwalGa05.pdf PDF] ] Garland T. (2003). Selection experiments: an under-utilized tool in biomechanics and organismal biology. Ch.3, "Vertebrate Biomechanics and Evolution" ed. Bels VL, Gasc JP, Casinos A. [http://www.biology.ucr.edu/people/faculty/Garland/Garland_2003.pdf PDF] ]

Online experiments in artificial selection

* [http://facemaker.redshiftmedia.com Face Maker] (firefox only)
* [http://www.mutatingpictures.com Mutating Pictures]

References

ee also

* Animal breeding
* Plant breeding
* Experimental evolution
* Gene pool
* Genetic engineering
* Inbreeding
* Marker assisted selection
* Quantitative genetics
* Selective breeding
* Smart breeding


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Look at other dictionaries:

  • artificial selection — artificial selection. См. искусственный отбор. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • artificial selection — noun : the process of modifying organisms by selection in breeding controlled by man * * * a process in the breeding of animals and in the cultivation of plants by which the breeder chooses to perpetuate only those forms having certain desirable… …   Useful english dictionary

  • artificial selection — dirbtinė atranka statusas T sritis augalininkystė apibrėžtis Augalų veislės gerinimas, atrenkant geresniuosius individus. atitikmenys: angl. artificial selection rus. искусственный отбор …   Žemės ūkio augalų selekcijos ir sėklininkystės terminų žodynas

  • artificial selection — selection of parental fish in a breeding programme designed to produce specific characters or traits in the young …   Dictionary of ichthyology

  • artificial selection — a process in the breeding of animals and in the cultivation of plants by which the breeder chooses to perpetuate only those forms having certain desirable inheritable characteristics. * * *       in biology, the selective breeding of animals and… …   Universalium

  • artificial selection — the interference by humans in the selection of the genotypes to produce succeeding generations of a given organism …   Medical dictionary

  • artificial selection — /ˌatəfɪʃəl səˈlɛkʃən/ (say .ahtuhfishuhl suh lekshuhn) noun See selection (def. 7) …   Australian English dictionary

  • artificial selection — noun intervention by humans in the breeding of plants or animals in order to preserve selected genetic traits …   Wiktionary

  • artificial selection — artifi′cial selec′tion n. gen a process in the breeding of animals and in the cultivation of plants by which the breeder chooses to perpetuate only those forms having certain desirable inheritable characteristics …   From formal English to slang

  • artificial selection — The practice of choosing individuals from a population for reproduction, usually because these individuals possess one or more desirable traits …   Glossary of Biotechnology


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