scholarly journals A Family-Based Joint Test for Mean and Variance Heterogeneity for Quantitative Traits

2014 ◽  
Vol 79 (1) ◽  
pp. 46-56 ◽  
Author(s):  
Ying Cao ◽  
Taylor J. Maxwell ◽  
Peng Wei
Keyword(s):  
Quantitative Traits ◽  
Variance Heterogeneity ◽  
Mean And Variance ◽  
Family Based

scholarly journals Fluxes and Metabolic Pools as Model Traits for Quantitative Genetics. I. The L-Shaped Distribution of Gene Effects

Genetics ◽  
1999 ◽  
Vol 153 (4) ◽  
pp. 2001-2012 ◽  
Author(s):  
Bruno Bost ◽  
Christine Dillmann ◽  
Dominique de Vienne
Keyword(s):  
Enzyme Activity ◽  
Metabolic Pathways ◽  
Quantitative Traits ◽  
Intrinsic Property ◽  
Gene Effects ◽  
Analytical Approximations ◽  
Mean And Variance ◽  
The Individual ◽  
Metabolic Control Theory ◽  
Control Coefficients

Abstract The fluxes through metabolic pathways can be considered as model quantitative traits, whose QTL are the polymorphic loci controlling the activity or quantity of the enzymes. Relying on metabolic control theory, we investigated the relationships between the variations of enzyme activity along metabolic pathways and the variations of the flux in a population with biallelic QTL. Two kinds of variations were taken into account, the variation of the average enzyme activity across the loci, and the variation of the activity of each enzyme of the pathway among the individuals of the population. We proposed analytical approximations for the flux mean and variance in the population as well as for the additive and dominance variances of the individual QTL. Monte Carlo simulations based on these approximations showed that an L-shaped distribution of the contributions of individual QTL to the flux variance (R2) is consistently expected in an F2 progeny. This result could partly account for the classically observed L-shaped distribution of QTL effects for quantitative traits. The high correlation we found between R2 value and flux control coefficients variance suggests that such a distribution is an intrinsic property of metabolic pathways due to the summation property of control coefficients.

scholarly journals The impact of genotyping error on family-based analysis of quantitative traits

2001 ◽  
Vol 9 (2) ◽  
pp. 130-134 ◽  
Author(s):  
Gonçalo R Abecasis ◽  
Stacey S Cherny ◽  
Lon R Cardon
Keyword(s):  
Quantitative Traits ◽  
Genotyping Error ◽  
Family Based ◽  
The Impact

scholarly journals Leveraging population information in family-based rare variant association analyses of quantitative traits

2016 ◽  
Vol 41 (2) ◽  
pp. 98-107 ◽  
Author(s):  
Yu Jiang ◽  
Yunqi Ji ◽  
Alexander B. Sibley ◽  
Yi-Ju Li ◽  
Andrew S. Allen
Keyword(s):  
Rare Variant ◽  
Quantitative Traits ◽  
Rare Variant Association ◽  
Association Analyses ◽  
Population Information ◽  
Family Based

Effect of mean and variance heterogeneity on genetic evaluations of Lesbos dairy sheep

2004 ◽  
Vol 88 (1-2) ◽  
pp. 107-115 ◽  
Author(s):  
M. Nikolaou ◽  
A.P. Kominakis ◽  
E. Rogdakis ◽  
S. Zampitis
Keyword(s):  
Variance Heterogeneity ◽  
Dairy Sheep ◽  
Mean And Variance ◽  
Genetic Evaluations

scholarly journals Quantitative traits under selection: derivations of distributions, higher moments, and the effects of recombination

2021 ◽  
Author(s):  
Reginald D Smith
Keyword(s):  
Quantitative Traits ◽  
Exact Formula ◽  
Breeding Value ◽  
Breeding Values ◽  
Mean And Variance ◽  
The Mean ◽  
The Impact ◽  
First Four Moments ◽  
First Time ◽  
Fertile Area

The mathematical theory of quantitative traits is over one hundred years old but it is still a fertile area for research and analysis. However, the effects of selection on a quantitative trait, while well understood for the effects on the mean and variance, have traditionally been difficult to attack from the perspective of analyzing the probability density of the breeding values and deriving higher (third and fourth) moments as well as analyzing the impact of recombination. In this paper, the exact formula for the breeding value distribution after selection is derived and, using new integral tables, the first four moments are given exact expressions for the first time. In addition, the effects of recombination on the full distribution of breeding values are demonstrated. Finally, the changes of GXE covariance in the selected parent population caused by factors similar to the Bulmer Effect are also investigated in detail.

A Family-Based Association Test for Repeatedly Measured Quantitative Traits Adjusting for Unknown Environmental and/or Polygenic Effects

2004 ◽  
Vol 3 (1) ◽  
pp. 1-27 ◽  
Author(s):  
Christoph Lange ◽  
Kristel van Steen ◽  
Toby Andrew ◽  
Helen Lyon ◽  
Dawn L DeMeo ◽  
...  
Keyword(s):  
Principal Component Analysis ◽  
Software Package ◽  
Quantitative Traits ◽  
Univariate Analysis ◽  
Principal Component ◽  
Genetic Effects ◽  
Association Test ◽  
Practical Relevance ◽  
Simulation Studies ◽  
Family Based

We propose a family-based association test, FBAT-PC, for studies with quantitative traits that are measured repeatedly. The traits may be influenced by partially or completely unknown factors that may vary for each measurement. Using generalized principal component analysis, FBAT-PC amplifies the genetic effects of each measurement by constructing an overall phenotype with maximal heritability. Analytically, and in the simulation studies, we compare FBAT-PC with standard methodology and assess both the heritability of the overall phenotype and the power of FBAT-PC. Compared to univariate analysis, FBAT-PC achieves power gains of up to 200%. Applications of FBAT-PC to an osteoporosis study and to an asthma study show the practical relevance of FBAT-PC. FBAT-PC has been implemented in the software package PBAT and is freely available at http://www.biostat.harvard.edu/~clange/default.htm.

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