scholarly journals THE DYNAMICS OF FINITE HAPLOID POPULATIONS WITH OVERLAPPING GENERATIONS. II. THE DIFFUSION APPROXIMATION

Genetics ◽  
1979 ◽  
Vol 92 (1) ◽  
pp. 339-351
Author(s):  
Ted H Emigh
Keyword(s):  
Population Size ◽  
Effective Population Size ◽  
Diffusion Approximation ◽  
Overlapping Generations ◽  
Mutation Rates ◽  
Reproductive Value ◽  
Selection Coefficient ◽  
Effective Population ◽  
Haploid Population

ABSTRACT The dynamics of a gene in a haploid population can be explained approximately by considering the average reproductive value of the gene. The dynamics of the average reproductive value are similar to those of a gene in a population with nonoverlapping generations with the following modifications: The effective population size, Ne, replaces N; the average mutation rates,μ* and v* replace μ and v; the average overall selection r*+(T-l)s** replaces s; and time is measured in terms of generations, T. The implications of the average selection coefficient to adaptive life histones are discussed.

scholarly journals Background selection theory overestimates effective population size for high mutation rates

2022 ◽  
Author(s):  
Joseph D Matheson ◽  
Joanna Masel
Keyword(s):  
Population Size ◽  
Effective Population Size ◽  
Deleterious Mutation ◽  
Neutral Theory ◽  
Mutation Rates ◽  
Background Selection ◽  
Effective Population ◽  
Selection Theory ◽  
Linkage Disequilibria ◽  
Genome Wide

Simple models from the neutral theory of molecular evolution are claimed to be flexible enough to incorporate the complex effects of background selection against linked deleterious mutations. Complexities are collapsed into an "effective" population size that specifies neutral genetic diversity. To achieve this, current background selection theory assumes linkage equilibrium among deleterious variants. Data do not support this assumption, nor do theoretical considerations when the genome-wide deleterious mutation is realistically high. We simulate genomes evolving under background selection, allowing the emergence of linkage disequilibria. With realistically high deleterious mutation rates, neutral diversity is much lower than predicted from previous analytical theory.

scholarly journals The genetic structure of populations of orchids and its evolutionary importance: understanding processes from patterns

Lankesteriana ◽  
2016 ◽  
Vol 3 (2) ◽  
Author(s):  
Raymond L. Tremblay
Keyword(s):  
Gene Flow ◽  
Natural Selection ◽  
Genetic Structure ◽  
Population Size ◽  
Effective Population Size ◽  
Genetic Drift ◽  
Mating Systems ◽  
Mutation Rates ◽  
Effective Population ◽  
Genetic Structure Of Populations

<div class="page" title="Page 1"><div class="layoutArea"><div class="column"><p><span>Evolution through either natural selection or genetic drift is dependent on variation at the genetic and mor- phological levels. Processes that influence the genetic structure of populations include mating systems, effective population size, mutation rates and gene flow among populations. </span></p></div></div></div>

scholarly journals A NOTE ON EFFECTIVE POPULATION SIZE WITH OVERLAPPING GENERATIONS

Genetics ◽  
1979 ◽  
Vol 92 (1) ◽  
pp. 317-322 ◽  
Author(s):  
William G Hill
Keyword(s):  
Population Size ◽  
Effective Population Size ◽  
Family Size ◽  
Overlapping Generations ◽  
Random Mating ◽  
Effective Size ◽  
Effective Population ◽  
Simple Derivation ◽  
Number Of Individuals

ABSTRACT A simple derivation is given far a formula obtained previously for the effective size of random-mating populations with overlapping generations. The effective papulation size is the same as that for a population with discrete generations having the same variance of lifetime family size and the same number of individuals entering the population per generation.

scholarly journals Joint estimation of selection intensity and mutation rate under balancing selection withapplications to HLA

2021 ◽  
Author(s):  
Montgomery Slatkin
Keyword(s):  
Population Size ◽  
Effective Population Size ◽  
Balancing Selection ◽  
Composite Likelihood ◽  
Joint Estimation ◽  
Likelihood Method ◽  
Mutation Rates ◽  
Symmetric Model ◽  
Effective Population ◽  
Selection Intensities

A composite likelihood method is introduced for jointly estimating the intensity of selection and the rate of mutation, both scaled by the effective population size, when there is balancing selection at a single multi-allelic locus in an isolated population at demographic equilibrium. The performance of the method is tested using simulated data. Average estimated mutation rates and selection intensities are close to the true values but there is considerable variation about the averages. Allowing for both population growth and population subdivision do not result in qualitative differences but the estimated mutation rates and selection intensities do not in general reflect the current effective population size. The method is applied to three class I (HLA-A, HLA-B and HLA-C) and two class II loci (HLA-DRB1 and HLA-DQA1) in the 1000 Genomes populations. Allowing for asymmetric balancing selection has only a slight effect on the results from the symmetric model. Mutations that restore symmetry of the selection model are preferentially retained because of the tendency of natural selection to maximize average fitness. However, slight differences in selective effects result in much longer persistence time of some alleles. Trans-species polymorphism (TSP), which is characteristic of MHC in vertebrates, is more likely when there are small differences in allelic fitness than when complete symmetry is assumed. Therefore, variation in allelic fitness expands the range of parameter values consistent with observations of TSP.

scholarly journals Temporal allele frequency change and estimation of effective size in populations with overlapping generations.

Genetics ◽  
1995 ◽  
Vol 139 (2) ◽  
pp. 1077-1090 ◽  
Author(s):  
P E Jorde ◽  
N Ryman
Keyword(s):  
Population Size ◽  
Effective Population Size ◽  
Allele Frequency ◽  
Overlapping Generations ◽  
Temporal Frequency ◽  
Effective Size ◽  
Frequency Change ◽  
Effective Population ◽  
Frequency Shifts ◽  
Frequency Changes

Abstract In this paper we study the process of allele frequency change in finite populations with overlapping generations with the purpose of evaluating the possibility of estimating the effective size from observations of temporal frequency shifts of selectively neutral alleles. Focusing on allele frequency changes between successive cohorts (individuals born in particular years), we show that such changes are not determined by the effective population size alone, as they are when generations are discrete. Rather, in populations with overlapping generations, the amount of temporal allele frequency change is dependent on the age-specific survival and birth rates. Taking this phenomenon into account, we present an estimator for effective size that can be applied to populations with overlapping generations.

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