Everything about Artificial Selection totally explained
» For alternate uses, see Selective breeding.
Artificial selection is the intentional breeding for certain traits, or combinations of traits, over others. 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's thought that domestication of crops by early humans was largely unintentional.
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's 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.
Online experiments in artificial selection
Further Information
Get more info on 'Artificial Selection'.
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