# selection coefficient

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## se·lec·tion co·ef·fi·cient (s),

the proportion of progeny or potential progeny not surviving to sexual maturity; usually defined artificially by expressing the fitness of a phenotype as a fraction of the mean or optimal fitness to give the relative fitness, and subtracting this fraction from unity. If the mean size of family in the population is 3.2 and that for a particular genotype is 2.4 then the fitness of the phenotype is 2.4/3.2 = 0.75 and the selection coefficient = 1 - 0.75 = .25.

## se·lec·tion co·ef·fi·cient

(s) (sĕ-lek'shŭn kō'ĕ-fish'ĕnt)
The proportion of progeny or potential progeny not surviving to sexual maturity; usually defined artificially by expressing the fitness of a phenotype as a fraction of the mean or optimal fitness to give the relative fitness, and subtracting this fraction from unity.If the mean size of family in the population is3.2 and that for a particular genotype is 2.4,then the fitness of the phenotype is 2.4/3.2 =0.75, and the selection coefficient =1- 0.75 =.25 = 5.

## selection coefficient

see SELECTION PRESSURE.

## selection

1. choosing the individual units to be included in a sample. See also random selection.
2. choosing the animals to be retained for breeding purposes; genetic selection.

artificial selection
selection based on human decisions.
selection coefficient
proportionate reduction in the average genetic contribution made by a specific genotype, relative to the contribution made by another genotype. Denoted by s.
selection criteria
the animal characteristic which is used in a selection program.
selection differential
a measure of the gain achieved by selection; the phenotypic superiority of selected individuals, compared to the population from which they were selected.
selection index
a single overall estimate of the patient's true breeding value obtained from as many sources of information as are available.
individual selection
selection on the results of performance testing of the subject.
selection intensity
the superiority of the individuals selected for breeding, relative to the population from which they were selected.
selection limit
the situation in which the entire population is homozygous for the same set of favorable genes; called also selection plateau.
selection/mutation balance
when the rate of removal of a gene from the population by selection equals the rate at which mutations occur.
selection plateau
see selection limit.
selection program
the method used to select individuals from a population to be used for breeding. Usually includes nomination of the characters to be selected, the optimum size of the population in which the program is to operate, the intensity of selection available, the accuracy of the selection procedures, lengths of the generations in the species, the target rate of response.
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References in periodicals archive ?
In the linear additive model, therefore, we can easily calculate the additive genetic variance and selection coefficient based on this theorem (Price, 1972; Hartl, 1988; Ewens, 1989).
which can be rewritten as the estimate of the selection coefficient s for each generation:
These values are classified as moderate to high effects (Cohen 1988), and they are qualitatively consistent with the selection coefficients calculated for young and mature demes (Table 4).
Several traits exhibited selection coefficients that did not differ between sites or populations, but were significantly different from zero.
j] are a common type of kin selection coefficient, the slope of recipient genotype on actor genotype.
Most previous studies of this vulnerability treated all mutations as having identical selection coefficients (e.
The selection coefficient on corolla flare increased from 7% at seed set to 17% at offspring recruitment.
Although we have not explored it extensively, this logic should also apply to mutations with nonadditive effects within loci, except that the equivalence would be obtained by using a selection coefficient of s in selfers and s/h in asexuals.
This is because overdominance does not maintain variation in highly inbred populations unless selection coefficients against the homozygous genotypes are nearly symmetrical, which is biologically implausible (Kimura and Ohta 1971, pp.
This is equivalent to a selection coefficient, s of 0.
Whether m will spread is determined by its effective selection coefficient, [s.

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