scholarly journals Methods for Estimating Demography and Detecting Between-Locus Differences in the Effective Population Size and Mutation Rate

2018 ◽  
Vol 36 (2) ◽  
pp. 423-433 ◽  
Author(s):  
Kai Zeng ◽  
Benjamin C Jackson ◽  
Henry J Barton
Genetics ◽  
1994 ◽  
Vol 136 (2) ◽  
pp. 685-692 ◽  
Author(s):  
Y X Fu

Abstract A new estimator of the essential parameter theta = 4Ne mu from DNA polymorphism data is developed under the neutral Wright-Fisher model without recombination and population subdivision, where Ne is the effective population size and mu is the mutation rate per locus per generation. The new estimator has a variance only slightly larger than the minimum variance of all possible unbiased estimators of the parameter and is substantially smaller than that of any existing estimator. The high efficiency of the new estimator is achieved by making full use of phylogenetic information in a sample of DNA sequences from a population. An example of estimating theta by the new method is presented using the mitochondrial sequences from an American Indian population.


Genetics ◽  
1997 ◽  
Vol 146 (4) ◽  
pp. 1489-1499 ◽  
Author(s):  
Yun-Xin Fu

A coalescent theory for a sample of DNA sequences from a partially selfing diploid population and an algorithm for simulating such samples are developed in this article. Approximate formulas are given for the expectation and the variance of the number of segregating sites in a sample of k sequences from n individuals. Several new estimators of the important parameters θ = 4Nμ and the selfing rate s, where N and μ are, respectively, the effective population size and the mutation rate per sequence per generation, are proposed and their sampling properties are studied.


Genetics ◽  
1977 ◽  
Vol 85 (2) ◽  
pp. 331-337
Author(s):  
Wen-Hsiung Li

ABSTRACT Watterson's (1975) formula for the steady-state distribution of the number of nucleotide differences between two randomly chosen cistrons in a finite population has been extended to transient states. The rate for the mean of this distribution to approach its equilibrium value is 1/2 N and independent of mutation rate, but that for the variance is dependent on mutation rate, where N denotes the effective population size. Numerical computations show that if the heterozygosity (i.e., the probability that two cistrons are different) is low, say of the order of 0.1 or less, the probability that two cistrons differ at two or more nucleotide sites is less than 10 percent of the heterozygosity, whereas this probability may be as high as 50 percent of the heterozygosity if the heterozygosity is 0.5. A simple estimate for the mean number (d) of site differences between cistrons is d = h/(1 - h) where h is the heterozygosity. At equilibrium, the probability that two cistrons differ by more than one site is equal to h  2, the square of heterozygosity.


2020 ◽  
Author(s):  
John T. McCrone ◽  
Robert J. Woods ◽  
Arnold S. Monto ◽  
Emily T. Martin ◽  
Adam S. Lauring

AbstractThe global evolutionary dynamics of influenza viruses ultimately derive from processes that take place within and between infected individuals. Recent work suggests that within-host populations are dynamic, but an in vivo estimate of mutation rate and population size in naturally infected individuals remains elusive. Here we model the within-host dynamics of influenza A viruses using high depth of coverage sequence data from 200 acute infections in an outpatient, community setting. Using a Wright-Fisher model, we estimate a within-host effective population size of 32-72 and an in vivo mutation rate of 3.4×10−6 per nucleotide per generation.


PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2549 ◽  
Author(s):  
Séverine Fourdrilis ◽  
Patrick Mardulyn ◽  
Olivier J. Hardy ◽  
Kurt Jordaens ◽  
António Manuel de Frias Martins ◽  
...  

We report the presence of mitochondrial DNA (mtDNA) hyperdiversity in the marine periwinkleMelarhaphe neritoides(Linnaeus, 1758), the first such case among marine gastropods. Our dataset consisted of concatenated 16S-COI-Cytbgene fragments. We used Bayesian analyses to investigate three putative causes underlying genetic variation, and estimated the mtDNA mutation rate, possible signatures of selection and the effective population size of the species in the Azores archipelago. The mtDNA hyperdiversity inM. neritoidesis characterized by extremely high haplotype diversity (Hd= 0.999 ± 0.001), high nucleotide diversity (π= 0.013 ± 0.001), and neutral nucleotide diversity above the threshold of 5% (πsyn= 0.0677). Haplotype richness is very high even at spatial scales as small as 100m2. Yet, mtDNA hyperdiversity does not affect the ability of DNA barcoding to identifyM. neritoides. The mtDNA hyperdiversity inM. neritoidesis best explained by the remarkably high mutation rate at the COI locus (μ= 5.82 × 10−5per site per yearorμ= 1.99 × 10−4mutations per nucleotide site per generation), whereas the effective population size of this planktonic-dispersing species is surprisingly small (Ne= 5, 256; CI = 1,312–3,7495) probably due to the putative influence of selection. Comparison with COI nucleotide diversity values in other organisms suggests that mtDNA hyperdiversity may be more frequently linked to highμvalues and that mtDNA hyperdiversity may be more common across other phyla than currently appreciated.


Genetics ◽  
1997 ◽  
Vol 145 (3) ◽  
pp. 833-846 ◽  
Author(s):  
Jody Hey ◽  
John Wakeley

Population genetic models often use a population recombination parameter 4Nc, where N is the effective population size and c is the recombination rate per generation. In many ways 4Nc is comparable to 4Nu, the population mutation rate. Both combine genome level and population level processes, and together they describe the rate of production of genetic variation in a population. However, 4Nc is more difficult to estimate. For a population sample of DNA sequences, historical recombination can only be detected if polymorphisms exist, and even then most recombination events are not detectable. This paper describes an estimator of 4Nc, hereafter designated γ (gamma), that was developed using a coalescent model for a sample of four DNA sequences with recombination. The reliability of γ was assessed using multiple coalescent simulations. In general γ has low to moderate bias, and the reliability of γ is comparable, though less, than that for a widely used estimator of 4Nu. If there exists an independent estimate of the recombination rate (per generation, per base pair), γ can be used to estimate the effective population size or the neutral mutation rate.


Author(s):  
Bruce Walsh ◽  
Michael Lynch

This chapter examines the relative strengths of the nonadaptive evolutionary forces (drift, mutation, recombination) acting on genomes. It reviews estimators for effective population size, mutation rate, and recombination rate, and summarizes the known genomic results over a wide range of taxa. The mutation rate tends to be lower in organisms with larger effective population sizes, consistent with the drift-barrier hypothesis wherein selection is ineffective when it is less than the reciprocal of the effective population size.


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