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Deleterious mutations, apparent stabilizing selection and the maintenance of quantitative variation

Article Abstract:

A simple model is employed to study the dependence of stabilizing selection on the rate of deleterious mutations in a quantitative trait. The model takes the epistatic selection against deleterious genetic alteration into account. The additive genetic variance of the trait is directly proportional to the mean of deleterious mutations, the fraction of deleterious mutations affecting the trait and the variance of pleiotropic effects. On the other hand, in measuring the trait in in terms of additive standard deviation, the variance approximates the selection coefficient against the mutation.

Research, Models, Mutation (Biology), Mutation, Variation (Biology)

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Dynamics of cytoplasmic incompatibility and mtDNA variation in natural Drosophila simulans populations

Article Abstract:

A study was conducted to examine cytoplasmic incompatibility and mitochondrial DNA (mtDNA) variations in Drosophila simulans populations. Under cytoplasmic incompatibility, mating between infected males and unifected females decrease egg hatch. The spreading infection is related to the frequency of mtDNA changes. Results show that imperfect female transmission of infection occurs more often than paternal transmission.

Genetic aspects, Mitochondrial membranes, Mitochondrial membrane, Drosophilidae, Cytoplasmic inheritance

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The effect of selection on the phenotypic variance

Article Abstract:

A study focussed on the within-generation alterations of phenotypic variance resulting from selection W(x) which influences a quantitative attribute x. If the attribute possesses Gaussian distribution prior to selection, its variance is lowered if the second derivative of the logarithm of W(x) is negative for all values of x, but its variance is enhanced if it is positive for all values of x.

Analysis, Phenotype, Phenotypes

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