BioConcepts

directional selectiongerichtete Selektion (ger.)

• Selection that changes the frequency of an allele in a particular, constant direction, either towards or away from fixation of that allele. It is often used in agriculture and horticulture to produce a shift in the population mean of a trait desired by humans. For example, the breeder might select for cows that yield more milk. (Oxford Dict. of Zoology 2009)
  category selection see also disruptive selection stabilizing selection

  1953

  the action of selection may be classified into three basic types. It may favour one extreme phenotype at the expense of all others, as is commonly the case with artificial selection in domesticated plants and animals (directional selection). It may favour the average expression at the expense of both extremes (stabilizing selection). Or, finally, it may favour both extremes simultaneously, though not necessarily to the same extent, at the expense of the average (disruptive selection).

  Mather, K. (1953). The genetical structure of populations. Symp. Soc. Exper. Biol. 7, 66-95: 73.