Intergradation

Intergradation

In zoology, intergradation is the way in which two distinct subspecies are connected via areas where populations are found that have the characteristics of both. There are two types of intergradation:

Primary intergradation: Occurs in cases were two subspecies are connected via one or more intermediate populations, each of which are in turn intermediate to their adjacent populations and exhibit more or less the same amount of variability as any other population within the species. Adjacent populations and subspecies are subject to cline intergradation, and in these situations it is usually taken for granted that the clines are causally related (by selection) to environmental gradients.Mayr E, Ashlock PD. 1991. Principles of Systematic Zoology. Second edition. McGraw-Hill, Inc. 475 pp. ISBN 0-07-041144-1.]

Secondary intergradation: When contact between a geographically isolated subspecies is reestablished with the main body of the species or with another isolate, interbreeding takes place as long as the isolate has not yet evolved an effective set of isolating mechanisms. Consequently, a relatively distinct zone or belt of hybridization will develop depending on the degree of genetic and phenotypic difference that was achieved by the previously isolated subspecies.

References


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Look at other dictionaries:

  • intergradation — intergradation. См. интерградация. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • Intergradation — L intergradation est fréquemment observée entre les diverses sous espèces du Moineau domestique. L intergradation est, en zoologie ou en botanique, la façon dont deux sous espèces distinctes sont reliées entre elles par des zones où les… …   Wikipédia en Français

  • Intergradation — Unter Intergradation wird das Vermischen zweier oder mehrerer Subspezies einer Art in einem regionalen Gebiet verstanden. Ein Beispiel ist die Intergradation der beiden Subspezies der Aaskrähe (Corvus corone), die entlang einer Linie von… …   Deutsch Wikipedia

  • intergradation — noun Date: 1874 the condition of an individual or population that intergrades • intergradational adjective …   New Collegiate Dictionary

  • intergradation — intergradational, adj. /in teuhr gray day sheuhn/, n. 1. the act or process of intergrading or the state of being intergraded. 2. an evolutionary process by which different species of organisms tend to merge through a series of intermediate… …   Universalium

  • intergradation — noun a gradual merging of two things See Also: intergrade …   Wiktionary

  • intergradation — in·ter·gradation …   English syllables

  • intergradation — n. the process of merging together by gradual change of the constituents …   Useful english dictionary

  • secondary intergradation — The intergradation or hybridization of two distinct and previously isolated populations that have reestablished contact; see primary intergradation …   Dictionary of invertebrate zoology

  • primary intergradation — primary intergradation. См. первичная интерградация. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

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