random genetic drift


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random genetic drift

Random genetic driftclick for a larger image
Fig. 265 Random genetic drift . The frequency of one allele of a gene over many generations. The continuous line represents population A, the broken line population B.

random genetic drift (RGD) or Sewall Wright effect

changes in ALLELE frequency in a population from one generation to another due to chance fluctuations. RGD is important in small populations which are subject to sampling error and where an allele can be lost (0% frequency) or fixed (100%).

The phenomenon was first described by the American geneticist Sewall Wright.

References in periodicals archive ?
Therefore, the effect of random genetic drift is stronger with lower [f.
They concluded that the effect of random genetic drift was substantial in Canadian Duroc and Lacombe populations.
In the case of the less constrained pleiotropic system, part of the loci are now only submitted to random genetic drift and thus ought to be affected by the size of the population independently of the product Nih.
Therefore, the fixation index for each population, which corresponds to the loss of within-population heterozygosity (Table 5), most likely reflects the expected inbreeding due to random genetic drift rather than selection and fixation of genes linked to the marker loci used in this study.
Mallet (1986), on the other hand, invokes the SB process, suggesting that random genetic drift establishes a novel pattern in a small region.
However, it is also possible and likely that populations diverge with partial to complete dominance, depending on the gene frequencies in the opposite population and the amount of random genetic drift (Keeratinijakal and Lamkey, 1993b; Hanson and Moll, 1986).
In contrast, Mayr emphasized the role of random genetic drift in producing reproductive isolation and morphological innovations.
The potential for random genetic drift is a major concern in the relatively small populations associated with regeneration.
The simultaneous production of inbred and noninbred mice each generation within each replicate stock removes the possibility that environmental shifts, directional selection in the lab, or random genetic drift over time contribute to the "depression" reported for the inbred lines.
Also, if too few individuals were intermated, the primary force changing allele frequency would be random genetic drift rather than selection.
mutation, random genetic drift, and selection), and provides a link between those processes and the macroevolutionary pattern observed in a set of comparative or interspecific data.