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Learn more about "Artificial Selection"

Artificial selection

Artificial selection (or selective breeding) describes intentional breeding for certain traits, or combination of traits.The term was utilized by Charles Darwin in contrast to natural selection, in which the differential reproduction of organisms with certain traits is attributed to improved survival or reproductive ability (“Darwinian fitness”). As opposed to artificial selection, in which humans favor specific traits, in natural selection the environment acts as a sieve through which only certain variations can pass. The deliberate exploitation of artificial selection has become very common in experimental biology, as well as the discovery and invention of new drugs. Artificial selection can also be unintentional; it is thought that domestication of crops by early humans was largely unintentional.Artificial Selection PowerPoint, University of Wisconsin-Madison

Historical development

The notion of artificial selection was expressed by the Persian people|Persian polymath Abu Rayhan Biruni in the 11th century. He suggested the idea in his book entitled ''India'', and gave various examples of it, some of which are described in the following statement by Biruni: 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 intentional animal husbandry|animal and plant breeding from individuals that showed desirable characteristics, and discouraging the breeding of individuals with less desirable characteristics. Darwin used the term twice in the 1859 first edition of his work ''On the Origin of Species'', in Chapter IV: Natural Selection, and in Chapter VI: Difficulties on Theory –

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 used by Charles Darwin 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 cell (biology)|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 gene expression|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 Systematic Evolution of Ligands by Exponential Enrichment|''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, Theodore Garland, Jr.|Garland T, Jr. (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.PDF Theodore Garland, Jr.|Garland T, Jr. (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. PDF Theodore Garland, Jr.|Garland T, Jr., Rose MR, eds. (2009). ''Experimental Evolution: Concepts, Methods, and Applications of Selection Experiments''.University of California Press, Berkeley, California. In press.

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