scholarly journals Allele frequencies at microsatellite loci: the stepwise mutation model revisited.

Genetics ◽  
1993 ◽  
Vol 133 (3) ◽  
pp. 737-749 ◽  
Author(s):  
A M Valdes ◽  
M Slatkin ◽  
N B Freimer
Keyword(s):  
Mutation Rate ◽  
Microsatellite Loci ◽  
Allele Frequencies ◽  
Stepwise Mutation Model ◽  
Human Populations ◽  
Effective Population ◽  
Allele Size ◽  
Frequency Distributions ◽  
Mutation Model ◽  
Stepwise Mutation

Abstract We summarize available data on the frequencies of alleles at microsatellite loci in human populations and compare observed distributions of allele frequencies to those generated by a simulation of the stepwise mutation model. We show that observed frequency distributions at 108 loci are consistent with the results of the model under the assumption that mutations cause an increase or decrease in repeat number by one and under the condition that the product Nu, where N is the effective population size and u is the mutation rate, is larger than one. We show that the variance of the distribution of allele sizes is a useful estimator of Nu and performs much better than previously suggested estimators for the stepwise mutation model. In the data, there is no correlation between the mean and variance in allele size at a locus or between the number of alleles and mean allele size, which suggests that the mutation rate at these loci is independent of allele size.

scholarly journals A measure of population subdivision based on microsatellite allele frequencies.

Genetics ◽  
1995 ◽  
Vol 139 (1) ◽  
pp. 457-462 ◽  
Author(s):  
M Slatkin
Keyword(s):  
Microsatellite Loci ◽  
Allele Frequencies ◽  
Stepwise Mutation Model ◽  
Population Subdivision ◽  
Population Divergence ◽  
Migration Rates ◽  
Mutation Model ◽  
Subdivided Populations ◽  
Stepwise Mutation ◽  
Unbiased Estimates

Abstract A new measure of the extent of population subdivision as inferred from allele frequencies at microsatellite loci is proposed and tested with computer simulations. This measure, called R(ST), is analogous to Wright's F(ST) in representing the proportion of variation between populations. It differs in taking explicit account of the mutation process at microsatellite loci, for which a generalized stepwise mutation model appears appropriate. Simulations of subdivided populations were carried out to test the performance of R(ST) and F(ST). It was found that, under the generalized stepwise mutation model, R(ST) provides relatively unbiased estimates of migration rates and times of population divergence while F(ST) tends to show too much population similarity, particularly when migration rates are low or divergence times are long [corrected].

scholarly journals An evaluation of genetic distances for use with microsatellite loci.

Genetics ◽  
1995 ◽  
Vol 139 (1) ◽  
pp. 463-471 ◽  
Author(s):  
D B Goldstein ◽  
A Ruiz Linares ◽  
L L Cavalli-Sforza ◽  
M W Feldman
Keyword(s):  
Microsatellite Loci ◽  
Phylogenetic Reconstruction ◽  
Genetic Distances ◽  
Stepwise Mutation Model ◽  
Mutation Model ◽  
Stepwise Mutation ◽  
The Difference ◽  
Nei's Distance ◽  
Infinite Alleles Model ◽  
Overall Reliability

Abstract Mutations of alleles at microsatellite loci tend to result in alleles with repeat scores similar to those of the alleles from which they were derived. Therefore the difference in repeat score between alleles carries information about the amount of time that has passed since they shared a common ancestral allele. This information is ignored by genetic distances based on the infinite alleles model. Here we develop a genetic distance based on the stepwise mutation model that includes allelic repeat score. We adapt earlier treatments of the stepwise mutation model to show analytically that the expectation of this distance is a linear function of time. We then use computer simulations to evaluate the overall reliability of this distance and to compare it with allele sharing and Nei's distance. We find that no distance is uniformly superior for all purposes, but that for phylogenetic reconstruction of taxa that are sufficiently diverged, our new distance is preferable.

scholarly journals VNTR allele frequency distributions under the stepwise mutation model: a computer simulation approach.

Genetics ◽  
1993 ◽  
Vol 134 (3) ◽  
pp. 983-993 ◽  
Author(s):  
M D Shriver ◽  
L Jin ◽  
R Chakraborty ◽  
E Boerwinkle
Keyword(s):  
Tandem Repeats ◽  
Repeat Unit ◽  
Allele Size ◽  
Frequency Distributions ◽  
Mutation Model ◽  
Stepwise Mutation ◽  
One Step ◽  
Simulation Results ◽  
Summary Measures ◽  
The One

Abstract Variable numbers of tandem repeats (VNTRs) are a class of highly informative and widely dispersed genetic markers. Despite their wide application in biological science, little is known about their mutational mechanisms or population dynamics. The objective of this work was to investigate four summary measures of VNTR allele frequency distributions: number of alleles, number of modes, range in allele size and heterozygosity, using computer simulations of the one-step stepwise mutation model (SMM). We estimated these measures and their probability distributions for a wide range of mutation rates and compared the simulation results with predictions from analytical formulations of the one-step SMM. The average heterozygosity from the simulations agreed with the analytical expectation under the SMM. The average number of alleles, however, was larger in the simulations than the analytical expectation of the SMM. We then compared our simulation expectations with actual data reported in the literature. We used the sample size and observed heterozygosity to determine the expected value, 5th and 95th percentiles for the other three summary measures, allelic size range, number of modes and number of alleles. The loci analyzed were classified into three groups based on the size of the repeat unit: microsatellites (1-2 base pair (bp) repeat unit), short tandem repeats [(STR) 3-5 bp repeat unit], and minisatellites (15-70 bp repeat unit). In general, STR loci were most similar to the simulation results under the SMM for the three summary measures (number of alleles, number of modes and range in allele size), followed by the microsatellite loci and then by the minisatellite loci, which showed deviations in the direction of the infinite allele model (IAM). Based on these differences, we hypothesize that these three classes of loci are subject to different mutational forces.

scholarly journals Haplogroup-specific deviation from the stepwise mutation model at the microsatellite loci DYS388 and DYS392

2001 ◽  
Vol 9 (1) ◽  
pp. 22-26 ◽  
Author(s):  
Almut Nebel ◽  
Dvora Filon ◽  
Carsten Hohoff ◽  
Marina Faerman ◽  
Bernd Brinkmann ◽  
...  
Keyword(s):  
Microsatellite Loci ◽  
Stepwise Mutation Model ◽  
Mutation Model ◽  
Stepwise Mutation

scholarly journals Recent demographic histories of temperate deciduous trees inferred from microsatellite markers

2020 ◽  
Author(s):  
Yu Cao ◽  
Da-Yong Zhang ◽  
Yan-Fei Zeng ◽  
Wei-Ning Bai
Keyword(s):  
Microsatellite Markers ◽  
Tree Species ◽  
Demographic History ◽  
Stepwise Mutation Model ◽  
Moderate Increase ◽  
Effective Population ◽  
Mutation Model ◽  
Cool Temperate ◽  
Stepwise Mutation ◽  
Population Demographic

Abstract Background Accurate inference of demographic histories of temperate tree species can aid our understanding of current climate change as a driver of evolution. Microsatellites are more suitable for reflecting recent historical events due to their high mutation rates. However, most programs analyze microsatellite data following a strict stepwise mutation model (SMM), which could cause false detection of population shrinkage when microsatellite mutation is not according with SMM. Results This study aims to reconstruct the recent demographic histories of five cool-temperate tree species, Quercus mongolica, Q. liaotungensis, Juglans cathayensis, J. mandshurica and J. ailantifolia, in eastern Asia by using 19 microsatellite markers and two methods considering generalized stepwise mutation model (GSM) (MIGRAINE and VarEff). Both types of software revealed that all populations experienced expansions after the Last Glacial Maximum (LGM). In particular, J. cathayensis experienced a more serious bottleneck in its history than the other species, leading to a smaller effective population of ancestors, while Q. mongolica showed only a moderate increase in population size and remained stable after the expansion. In addition, the point estimates of the multistep mutation proportion in the generalized stepwise mutation model (pGSM) in all populations were between 0.50 and 0.65, which indicates that when inferring population demographic history of the above forest species using microsatellite molecular markers, it is better to assume a GSM rather than a SMM. Conclusions This study provides the first direct evidence that five cool-temperate tree species in East Asia have experienced expansions after the LGM using microsatellites data. Moreover, since the mutation model of microsatellite have a vital influence on demographic inference, combining multiple software programs such as MIGRAINE and VarEff can effectively reduce unnecessary errors caused by inappropriate model selection and prior setting.

scholarly journals Dynamics of Microsatellite Divergence Under Stepwise Mutation and Proportional Slippage/Point Mutation Models

Genetics ◽  
2001 ◽  
Vol 159 (2) ◽  
pp. 839-852 ◽  
Author(s):  
Peter P Calabrese ◽  
Richard T Durrett ◽  
Charles F Aquadro
Keyword(s):  
Point Mutations ◽  
Genetic Distances ◽  
Mutational Bias ◽  
Human Populations ◽  
Mutation Model ◽  
Perfect Repeat ◽  
Stepwise Mutation ◽  
Equilibrium Distributions ◽  
Theoretical Results ◽  
Polymerase Slippage

Abstract Recently Kruglyak, Durrett, Schug, and Aquadro showed that microsatellite equilibrium distributions can result from a balance between polymerase slippage and point mutations. Here, we introduce an elaboration of their model that keeps track of all parts of a perfect repeat and a simplification that ignores point mutations. We develop a detailed mathematical theory for these models that exhibits properties of microsatellite distributions, such as positive skewness of allele lengths, that are consistent with data but are inconsistent with the predictions of the stepwise mutation model. We use our theoretical results to analyze the successes and failures of the genetic distances (δμ)2 and DSW when used to date four divergences: African vs. non-African human populations, humans vs. chimpanzees, Drosophila melanogaster vs. D. simulans, and sheep vs. cattle. The influence of point mutations explains some of the problems with the last two examples, as does the fact that these genetic distances have large stochastic variance. However, we find that these two features are not enough to explain the problems of dating the human-chimpanzee split. One possible explanation of this phenomenon is that long microsatellites have a mutational bias that favors contractions over expansions.

scholarly journals Mutation Rate Model Used in the DNA VIEW Program

2020 ◽  
Vol 10 (10) ◽  
pp. 3585 ◽  
Author(s):  
Tomasz Krajka
Keyword(s):  
Computer Simulation ◽  
Allele Frequency ◽  
Mutation Rate ◽  
Allele Frequencies ◽  
Rate Model ◽  
Dna Database ◽  
Mutation Model ◽  
Population Allele Frequency ◽  
Frequency Changes

The first problem considered in this paper is the problem of correctness of a mutation model used in the DNA VIEW program. To this end, we theoretically predict population allele frequency changes in time according to this and similar models (we determine the limit frequencies of alleles—they are uniformly distributed). Furthermore, we evaluate the speed of the above changes using computer simulation applied to our DNA database. Comparing uniformly distributed allele frequencies with these existing in the population (for example, using entropy), we conclude that this mutation model is not correct. The evolution does not follow this direction (direction of uniformly distributed frequencies). The second problem relates to the determination of the extent to which an incorrect mutation model can disturb DNA VIEW program results. We show that in typical computations (simple paternity testing without maternal mutation) this influence is negligible, but in the case of maternal mutation, this should be taken into account. Furthermore, we show that this model is inconsistent from a theoretical viewpoint. Equivalent methods result in different error levels.

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