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Effective population size - Wikipedia, the free encyclopedia
In population genetics, the concept of effective population size N e was introduced by the American geneticist Sewall Wright, who wrote two landmark papers on it (Wright 1931, 1938). He de...
en.wikipedia.org/wiki/Effective_population_size |
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In real populations, the Hardy-Weinberg assumption of infinite population size is violated. Even in the absence of natural selection, the inevitable variance among individuals in the number of offspring that inherit their genes changes allele frequencies, an effect known as genetic drift. ... Changing Population Size...
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Effective population size is the number of individuals in a population who contribute offspring to the next generation. ... Population geneticists therefore often write Ne (for 'effective' population size) in the equations, rather than N. In practice, effective population sizes are usually lower than ecologically...
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effective population size of a population is the size of an ideal population which acts the same as the real population in question. ... Ne (as we abbreviate the effective size) can deal with assumptions 2 + 3. Later we will learn how to combine the effects of drift and selection.
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Another, and by far the most common approach, is to come up with a conversion formula that makes our actual population seem like the ``ideal'' population that we've been studying. That's exactly what effective population size is.
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The total effective size of a subdivided population can be expressed as a function of the mean within-deme effective population size and of FST (WRIGHT 1951 ), which describes the amount of between-deme differentiation relative to the variability in the set of populations as whole.
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In the past, moment and likelihood methods have been developed to estimate the effective population size (Ne) on the basis of the observed changes of marker allele frequencies over time, and these have been applied to a large variety of species and populations.
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Use of adequate effective population size in maize (Zea mays L.) recurrent selection programs is important because of random genetic drift and inbreeding depression.
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When collecting and regenerating genetic resources, genetic drift affects the representation of a population and occurs at two stages: when sampling the parents and when gametes are sampled from these parents. The variance effective population size [Ne(v)] quantifies genetic drift.
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Explaining a small effective size ... In a panmictic population, a selectively advantageous mutation evolves to fixation with a probability and at a rate that share a simple relationship to population size and the strength of selection.
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