Artificial selection 49039 224731126 2008-07-10T04:28:24Z 122.200.166.75 Artificial breeding is synonymous with Selective breeding {{for|alternate uses|Selective breeding}} [[Image:IMG013biglittledogFX wb.jpg|thumb|right|This [[Chihuahua (dog)|Chihuahua]] [[mixed-breed dog|mix]] and [[Great Dane]] show the wide range of dog breed sizes created using artificial selection.]] [[Image:Cornselection.jpg|thumb|right|Selective breeding transformed [[teosinte]]'s few fruitcases (left) into modern corn's rows of exposed kernels (right).]] '''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 (ecology)|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.<ref>[http://www.botany.wisc.edu/courses/botany_940/powerpoints/ArtificialSelection.ppt Artificial Selection powerpoint, University of Wisconsin-Madison]</ref> ==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 <nowiki>characteristics.</nowiki> ==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]], [[gene]]s 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 [[aptamer]]s, or [[nucleic acid]] fragments capable of binding specific [[organic compound]]s 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 time]]s and greater difficulty in breeding can make such projects challenging in vertebrates.<ref name="Swallow">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] </ref><ref name="Garland">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]</ref> ==Online experiments in artificial selection== * [http://facemaker.redshiftmedia.com Face Maker] (firefox only) * [http://www.mutatingpictures.com Mutating Pictures] ==References== <references/> ==Related Topics== * [[Plant breeding]] * [[Experimental evolution]] * [[Gene pool]] * [[Genetic engineering]] * [[Inbreeding]] * [[Marker assisted selection]] * [[Quantitative genetics]] * [[Selective breeding]] * [[Smart breeding]] {{evolution}} [[Category:Selection]] [[Category:Breeding]] [[ca:Selecció artificial]] [[da:Kunstig selektion]] [[es:Selección artificial]] [[he:ברירה מלאכותית]] [[lv:Selekcija]] [[ja:人為選択]] [[pl:Sztuczna selekcja]] [[pt:Seleção artificial]] [[ru:Селекция]] [[fi:Jalostus (biologia)]] [[uk:Селекція]] [[zh:人工選擇]]