Inbreeding depression

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A inbreeding depression is the reduction in power (susceptibility to disease at a higher coefficient of inbreeding in the population) of inbred populations. It occurs particularly in confined habitats in which the genetic variability of a population is limited and there may be a genetic bottleneck . This is the case, among other things, with small animal populations on islands in their habitat that do not allow exchange with other islands. In such populations, hereditary diseases can occur more frequently; see also Hereditary diseases in endogamous populations .

Inbreeding depression can also be a consequence of breeding programs in which the same selected plants or parent animals are repeatedly used for breeding (e.g. champion breeding in pedigree dogs ).

Due to the indivisibility of the genome at the level of the individual alleles , alleles are lost from the gene pool , the genetic diversity and thus the effective population size are gradually reduced. Due to the genetic uniformity of the population, inbreeding also occurs between pairs that are not closely related. The population can degenerate and become more susceptible to disease.

Under certain conditions, inbreeding depression can be overcome even with continued inbreeding. This phenomenon is known as purging .

See also


  • Thornhill, NW (1993): The Natural History of Inbreeding and Outbreeding - Theoretical and Empirical Perspectives . University of Chicago Press, ISBN 0-226-79854-2