BioConcepts

discontinuous variationdiskontinuierliche Variation (ger.)

• Clearly defined differences in a characteristic that can be observed in a population. Characteristics that are determined by different alleles at a single locus show discontinuous variation, e.g. garden peas are either wrinkled or smooth. (Oxford Dict. of Biology 2008)
  category mutation

  1891

  if, as may be alleged, there is little evidence that species may arise by what may be called discontinuous Variation—a Variation in kind—there is still less evidence that new forms can arise by those Variations in degree which at any given moment are capable of being arranged in a curve of Error; and no one as yet has ever indicated the way by which such Variations could lead to the constitution of new forms, at all events under the sole guidance of Natural Selection.

  Bateson, W. (1891). On the variation in floral symmetry of certain plants having irregular corollas (Scientific Papers of William Bateson, vol. 1, ed. R.C. Punnett, Cambridge 1928, 126-161): 159.

  1894

  the existence of sudden and discontinuous Variation, the existence, that is to say, of new forms having from their first beginning more or less of the kind of perfection that we associate with normality, is a fact that disposes, once and for all, of the attempt to interpret all perfection and definiteness of form as the work of Selection. The study of Variation leads us into the presence of whole classes of phenomena that are plainly incapable of such interpretations. […] I suggest in brief that the Discontinuity of Species results from the Discontinuity of Variation.

  Bateson, W. (1894). Materials for the Study of Variation Treated with Especial Regard to Discontinuity in the Origin of Species: 568.

  1937

  The genetic basis of continuous variation is probably similar to that of discontinuous variation

  Dobzhansky, T. (1937). Genetics and the Origin of Species: 60; cf. Weber, M. (1998). Die Architektur der Synthese: 92; 107.