Quantitative Genetic Variance Maintained by Fluctuating Selection with Overlapping Generations: Variance Components and Covariances

Evolution ◽  
1997 ◽  
Vol 51 (3) ◽  
pp. 682 ◽  
Author(s):  
Akira Sasaki ◽  
Stephen Ellner
Keyword(s):  
Variance Components ◽  
Overlapping Generations ◽  
Genetic Variance ◽  
Fluctuating Selection ◽  
Quantitative Genetic

scholarly journals Quantitative genetics and the evolution of ontogeny: I. Ontogenetic changes in quantitative genetic variance components in randombred mice

1983 ◽  
Vol 42 (1) ◽  
pp. 65-75 ◽  
Author(s):  
James M. Cheverud ◽  
Larry J. Leamy ◽  
William R. Atchley ◽  
J. J. Rutledge
Keyword(s):  
Maternal Effects ◽  
Environmental Effects ◽  
Variance Components ◽  
Genetic Variance ◽  
Tail Length ◽  
Head Length ◽  
Ontogenetic Changes ◽  
Trunk Length ◽  
Quantitative Genetic ◽  
Significant Difference

SUMMARYWe report the results of an ontogenetic analysis of quantitative genetic variance components with two replicates drawn from the randombred ICR strain of mice. A total of 432 mice from 108 full-sib families raised in a cross-fostering design were used to estimate direct effects heritability, maternal effects, and environmental effects for weight, head length, trunk length, trunk circumference, and tail length at 17, 24, 31, 38, 45, 52, 59, and 66 days of age. There was no significant difference in heritability between the replicates. Heritabilities either stayed more or less constant with age at about 0·30 (weight, trunk length, trunk circumference) or increased slightly with age (head length, tail length). Maternal effects decreased with age from a maximum of about 0·50 at weaning to about 0·15 at age 66 when growth was nearly complete. Environmental effects increased in relative importance during ontogeny.

scholarly journals Dissecting the genetic architecture of quantitative traits using genome-wide identity-by-descent sharing among full-sibs

2021 ◽  
Author(s):  
Antoine Fraimout ◽  
Zitong Li ◽  
Mikko J. Sillanpää ◽  
Pasi Rastas ◽  
Juha Merilä
Keyword(s):  
Natural Selection ◽  
Variance Components ◽  
Genetic Architecture ◽  
Quantitative Traits ◽  
Genetic Parameters ◽  
Genetic Variance ◽  
Identity By Descent ◽  
Quantitative Genetic ◽  
Genome Wide ◽  
Quantitative Genetic Parameters

ABSTRACTAdditive and dominance genetic variances underlying the expression of quantitative traits are important quantities for predicting short-term responses to selection, but they are notoriously challenging to estimate in most wild animal populations. Using estimates of genome-wide identity-by-descent (IBD) sharing from autosomal SNP loci, we estimated quantitative genetic parameters for traits known to be under directional natural selection in nine-spined sticklebacks (Pungitius pungitius) and compared these to traditional pedigree-based estimators. Using four different datasets, with varying sample sizes and pedigree complexity, we further assessed the performance of different Genomic Relationship Matrices (GRM) to estimate additive and dominance variance components. Large variance in IBD relationships allowed accurate estimation of genetic variance components, and revealed significant heritability for all measured traits, with negligible dominance contributions. Genome-partitioning analyses revealed that all traits have a polygenic basis and are controlled by genes at multiple chromosomes. The results demonstrate how large full-sib families of highly fecund vertebrates can be used to obtain accurate estimates quantitative genetic parameters to provide insights on genetic architecture of quantitative traits in non-model organisms from the wild. This approach should be particularly useful for studies requiring estimates of genetic variance components from multiple populations as for instance when aiming to infer the role of natural selection as a cause for population differentiation in quantitative traits.

scholarly journals What can genetic variation tell us about the evolution of senescence?

2009 ◽  
Vol 276 (1665) ◽  
pp. 2271-2278 ◽  
Author(s):  
Jacob A. Moorad ◽  
Daniel E.L. Promislow
Keyword(s):  
Genetic Variation ◽  
Variance Components ◽  
Genetic Parameters ◽  
Genetic Variance ◽  
Mutation Accumulation ◽  
Antagonistic Pleiotropy ◽  
Age Classes ◽  
Dominance Variance ◽  
Quantitative Genetic ◽  
Genetic Techniques

Quantitative genetic approaches have been developed that allow researchers to determine which of two mechanisms, mutation accumulation (MA) or antagonistic pleiotropy (AP), best explain observed variation in patterns of senescence using classical quantitative genetic techniques. These include the creation of mutation accumulation lines, artificial selection experiments and the partitioning of genetic variances across age classes. This last strategy has received the lion's share of empirical attention. Models predict that inbreeding depression (ID), dominance variance and the variance among inbred line means will all increase with age under MA but not under those forms of AP that generate marginal overdominance. Here, we show that these measures are not, in fact, diagnostic of MA versus AP. In particular, the assumptions about the value of genetic parameters in existing AP models may be rather narrow, and often violated in reality. We argue that whenever ageing-related AP loci contribute to segregating genetic variation, polymorphism at these loci will be enhanced by genetic effects that will also cause ID and dominance variance to increase with age, effects also expected under the MA model of senescence. We suggest that the tests that seek to identify the relative contributions of AP and MA to the evolution of ageing by partitioning genetic variance components are likely to be too conservative to be of general value.

Genetic variance components for female fertility in Iranian Holstein cows

2011 ◽  
Vol 139 (3) ◽  
pp. 277-280 ◽  
Author(s):  
Heydar Ghiasi ◽  
Abbas Pakdel ◽  
Ardeshir Nejati-Javaremi ◽  
Hassan Mehrabani-Yeganeh ◽  
Mahmood Honarvar ◽  
...  
Keyword(s):  
Variance Components ◽  
Genetic Variance ◽  
Female Fertility ◽  
Holstein Cows

Quantitative genetic variance in experimental fly populations evolving with or without environmental heterogeneity

Evolution ◽  
2015 ◽  
Vol 69 (10) ◽  
pp. 2735-2746 ◽  
Author(s):  
Yuheng Huang ◽  
John R. Stinchcombe ◽  
Aneil F. Agrawal
Keyword(s):  
Genetic Variance ◽  
Environmental Heterogeneity ◽  
Quantitative Genetic

scholarly journals The distribution of allelic effects under mutation and selection

1990 ◽  
Vol 55 (2) ◽  
pp. 111-117 ◽  
Author(s):  
Steven A. Frank ◽  
Montgomery Slatkin
Keyword(s):  
Assortative Mating ◽  
Genetic Variance ◽  
Price Equation ◽  
Genetic Character ◽  
Quantitative Genetic ◽  
Mutation And Selection

SummaryThe Price (1970, 1972) equation is applied to the problem of describing the changes in the moments of allelic effects caused by selection, mutation and recombination at loci governing a quantitative genetic character. For comparable assumptions the resulting equations are the same as those obtained by different means by Barton & Turelli (1987; Turelli & Barton, 1989). The Price equation provides a natural framework within which to examine certain kinds of non-additive allelic effects, recombination and assortative mating. The use of the Price equation is illustrated by finding the equilibrium genetic variance under multiplicative dominance and epistasis and under assortative mating at an additive locus. The limitations of the use of recursion equations for the moments of allelic effects are also discussed.

scholarly journals Genetic analysis of spike traits in two- and multi-rowed barley crosses

Genetika ◽  
2012 ◽  
Vol 44 (3) ◽  
pp. 475-482
Author(s):  
Milomirka Madic ◽  
Desimir Knezevic ◽  
Aleksandar Paunovic ◽  
Dragan Djurovic
Keyword(s):  
Variance Components ◽  
Genetic Variance ◽  
Grain Weight ◽  
Spike Length ◽  
Grain Number ◽  
Partial Dominance ◽  
Grain Number Per Spike ◽  
Diallel Crossing ◽  
Barley Genotypes ◽  
Mode Of Inheritance

Mode of inheritance and genetic variance components for spike length, grain number per spike and grain weight per spike were evaluated in four parental genotypes and their F1 and F2 hybrids obtained through incomplete diallel crossing. Multi-rowed barley genotypes HVW-247 and Partizan and two-rowed barley genotypes KG-15 and NS-293 were selected for the crossing based on the trait concept with the parents being divergent for spike length, grain number per spike and grain weight per spike. The average values for spike length in F1 and F2 generations were intermediate or close to those of the parent having longer spikes, with the mode of inheritance being partial dominance, dominance or overdominance, depending on the crossing combination. The six-rowed x six-rowed and two-rowed x two-rowed crossing combinations showed dominance of increased grain number per spike and increased grain weight per spike in the inheritance of grain number per spike and grain weight per spike, respectively, whereas the six-rowed x two-rowed cross was predominated by partial dominance.

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