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Rapid Adaptation of a Polygenic Trait After a Sudden Environmental Shift
A population genetic model of polygenic selection is analyzed to describe the short-term response of a quantitative trait after a sudden shift of the phenotypic optimum and it is found that when the effect sizes are small relative to a scaled mutation rate, small to moderate allele frequency changes occur in theShort-term phase in a synergistic fashion.
Loss of Least-Loaded Class in Asexual Populations Due to Drift and Epistasis
- K. Jain
- 11 March 2008
This work considers the dynamics of a nonrecombining haploid population of finite size that accumulates deleterious mutations irreversibly and finds explicit analytical expressions for the typical time between successive clicks of the ratchet for both nonepistatic and epistatic fitness functions.
Purifying Selection, Drift, and Reversible Mutation with Arbitrarily High Mutation Rates
A population genetics model that incorporates purifying selection, reversible mutations, and genetic drift is analyzed, assuming a stationary population size and finds that many more intermediate-frequency variants are expected than under standard models, even with moderately strong purifier selection.
Distributed ledger technology: Implications of blockchain for the securities industry
Response of Polygenic Traits Under Stabilizing Selection and Mutation When Loci Have Unequal Effects
An infinitely large population under stabilizing selection and mutation in which the allelic effects determining a polygenic trait vary between loci is considered, finding that when most effects are small, the genetic variance does not change appreciably during adaptation, and the time until the phenotypic mean reaches the optimum is short if the number of loci are large.
Modes of Rapid Polygenic Adaptation.
The key results are that polygenic adaptation may be a rapid process and can proceed via subtle or dramatic changes in the allele frequency depending on the sizes of the phenotypic effects relative to a threshold value.
Adaptation in simple and complex fitness landscapes
The stationary population distribution in simple, single peak fitness landscapes is discussed at length, with particular emphasis on the error threshold phenomenon.
Deterministic and Stochastic Regimes of Asexual Evolution on Rugged Fitness Landscapes
Whether the evolutionary trajectory is deterministic or stochastic depends on the effective mutational distance deff up to which the population can spread in genotype space, which is relevant to the interpretation of evolution experiments with microbial populations.
EVOLUTIONARY ADVANTAGE OF SMALL POPULATIONS ON COMPLEX FITNESS LANDSCAPES
This study indicates that an advantage for small populations is likely whenever the fitness landscape contains local maxima, which appears at intermediate time scales, which are long enough for trapping at local fitness maxima to have occurred but too short for peak escape by the creation of multiple mutants.