The Wright–Fisher model with varying selection

1986 ◽  
Vol 23 (2) ◽  
pp. 504-508 ◽  
Author(s):  
N. C. Weber
Keyword(s):  
Population Growth ◽  
Population Size ◽  
Sufficient Conditions ◽  
Selective Advantage ◽  
Fisher Model ◽  
Ultimate Homozygosity ◽  
Varying Population

The Wright–Fisher model with varying population size is examined in the case where the selective advantage varies from generation to generation. Models are considered where the selective advantage is not always in favour of a particular genotype. Sufficient conditions in terms of the selection coefficients and the population growth are given to ensure ultimate homozygosity.

The Wright–Fisher model with varying selection

1986 ◽  
Vol 23 (02) ◽  
pp. 504-508
Author(s):  
N. C. Weber
Keyword(s):  
Population Growth ◽  
Population Size ◽  
Sufficient Conditions ◽  
Selective Advantage ◽  
Fisher Model ◽  
Ultimate Homozygosity ◽  
Varying Population

The Wright–Fisher model with varying population size is examined in the case where the selective advantage varies from generation to generation. Models are considered where the selective advantage is not always in favour of a particular genotype. Sufficient conditions in terms of the selection coefficients and the population growth are given to ensure ultimate homozygosity.

Fixation in bisexual models with variable population sizes

1997 ◽  
Vol 34 (02) ◽  
pp. 436-448 ◽  
Author(s):  
M. Möhle
Keyword(s):  
Main Part ◽  
Sufficient Conditions ◽  
Moran Model ◽  
Fisher Model ◽  
Population Sizes ◽  
Variable Population ◽  
Allelic Type ◽  
Ultimate Homozygosity ◽  
Necessary And Sufficient ◽  
Forward Process

A general exchangeable bisexual model with variable population sizes is introduced. First the forward process, i.e. the number of certain descending pairs, is studied. For the bisexual Wright-Fisher model fixation of the descendants occurs, i.e. their proportion tends to 0 or 1 almost surely. The main part of this article deals with necessary and sufficient conditions for ultimate homozygosity, i.e. the proportion of an arbitrarily chosen allelic type tends to 0 or 1 almost surely. The results are applied to a bisexual Wright-Fisher model and to a bisexual Moran model.

Fixation in bisexual models with variable population sizes

1997 ◽  
Vol 34 (2) ◽  
pp. 436-448 ◽  
Author(s):  
M. Möhle
Keyword(s):  
Main Part ◽  
Sufficient Conditions ◽  
Moran Model ◽  
Fisher Model ◽  
Population Sizes ◽  
Variable Population ◽  
Allelic Type ◽  
Ultimate Homozygosity ◽  
Necessary And Sufficient ◽  
Forward Process

A general exchangeable bisexual model with variable population sizes is introduced. First the forward process, i.e. the number of certain descending pairs, is studied. For the bisexual Wright-Fisher model fixation of the descendants occurs, i.e. their proportion tends to 0 or 1 almost surely.The main part of this article deals with necessary and sufficient conditions for ultimate homozygosity, i.e. the proportion of an arbitrarily chosen allelic type tends to 0 or 1 almost surely. The results are applied to a bisexual Wright-Fisher model and to a bisexual Moran model.

scholarly journals A phylogenetic estimator of effective population size or mutation rate.

Genetics ◽  
1994 ◽  
Vol 136 (2) ◽  
pp. 685-692 ◽  
Author(s):  
Y X Fu
Keyword(s):  
Population Size ◽  
Effective Population Size ◽  
Mutation Rate ◽  
Dna Sequences ◽  
High Efficiency ◽  
Minimum Variance ◽  
Population Subdivision ◽  
Effective Population ◽  
Fisher Model ◽  
Mitochondrial Sequences

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.

A genealogical approach to variable-population-size models in population genetics

1986 ◽  
Vol 23 (02) ◽  
pp. 283-296 ◽  
Author(s):  
Peter Donnelly
Keyword(s):  
Population Genetics ◽  
Branching Process ◽  
Sufficient Conditions ◽  
Process Models ◽  
Moran Model ◽  
Fisher Model ◽  
Variable Population ◽  
Exchangeable Model ◽  
Necessary And Sufficient ◽  
Variable Population Size

A general exchangeable model is introduced to study gene survival in populations whose size changes without density dependence. Necessary and sufficient conditions for the occurrence of fixation (that is the proportion of one of the types tending to 1 with probability 1) are obtained. These are then applied to the Wright–Fisher model, the Moran model, and conditioned branching-process models. For the Wright–Fisher model it is shown that certain fixation is equivalent to certain extinction of one of the types, but that this is not the case for the Moran model.

scholarly journals Ethnic Immigration Policy Implementation (1992- 2009)

2013 ◽  
pp. 109-117
Author(s):  
Shugatai Amangul
Keyword(s):  
National Identity ◽  
Population Growth ◽  
Policy Implementation ◽  
Population Size ◽  
International Migration ◽  
Immigration Policy ◽  
International Affairs ◽  
Migration Process ◽  
Economic Stability ◽  
Positive Effect

After Kazakhstan declared its independence, it became a large perform­er in the worldwide international migration process. The attraction of social and economic stability (with an increase in the level of liv­ing standard), stable ethno-demographic and population growth, no nationalist struggles as well as positive geopolitical situations, have lead to a huge flow of immigrants to Kazakhstan in the years since independence. In this study, I have suggested that results of the ethnic immigration policy include strengthening the national identity, creating a positive effect on the ethno-demographic outcomes, and increasing the number of the population size over the last nineteen years. DOI: http://dx.doi.org/10.5564/mjia.v0i17.87 Mongolian Journal of International Affairs, No.17 2012: 109-117

scholarly journals Shifts in interregional proportions in population settlement over the territory of Russia in 2002-2017

2019 ◽  
Vol 3 (1) ◽  
pp. 21-37
Author(s):  
Pavel Kirillov ◽  
Alla Makhrova
Keyword(s):  
Population Growth ◽  
Population Size ◽  
Russian Federation ◽  
Turning Point ◽  
Medium Term ◽  
Local Growth ◽  
Population Redistribution ◽  
Migratory Movement ◽  
Federal Districts ◽  
The Russian Federation

Abstract The article deals with the trends of population size changes in the regions of the Russian Federation between 2002 and 2017 on the basis of data of all-Russian population censuses and current statistics. Components of population growth (natural and migratory movement of the population) are analyzed. In order to take into account the current situation of population size changes in the regions, which are largely of a “turning point” nature and partly inconsistent with the medium-term dynamics since the 2002 Census, the analysis is focused on the period from 2014 to 2017. The paper presents estimates of population size shifts at regional and macro-regional levels, identifies general and local growth centers and depopulation zones. Conclusions are drawn about general shifts in the proportions of population settlement over the territory of Russia and in certain macro-regions (federal districts). General conclusions about the trends of population redistribution across the territory of the country are given in the final part of the study.

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