文档介绍：Chapter 7
Population ic parameters of quantitative traits
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Heritability
A parameter measuring the relative importance of ic influence on the variation of a quantitative trait
Heritability in the broad sense
Heritability in the narrow sense
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Heritability
Equivalent definitions of h2
Regression of breeding value on phenotypic value
Squared correlation between breeding value and phenotypic value
3
Heritability
Basic properties of heritability
It is a population-specific parameter, . it depends on the ic structure of the population and the environment to which the population is subjected
It is not observable, but can be estimated with statistical methods
4
Estimation of Heritability (classical methods)
Basic rule: heritability is estimated from degree of resemblance between relatives
From regression of offspring on parent
From intraclass correlation between sibs
5
Offspring-parent regression analysis
Model
Phenotypic value of the
parent(single or mid- parent)
Phenotypic value of offspring(single or mean of a group)
Single parent:
Mid-parent:
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N = number of offspring-parent pairs
Estimation of regression coefficient
Offspring-parent regression analysis
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Preconditions
No relationship between different offspring-parent pairs
Equal phenotypic variance in males and femals
No maternal effect (for offspring-mother regression and offspring-mid-parent regression)
Offspring-parent regression analysis
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Precision of estimate (sampling variance)
or
Single parent:
Mid-parent:
Offspring-parent regression analysis
n - Number of offspring in each family
t - Intraclass correlation between offspring
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Optimal experimental design
Let the total number of offspring (nN) be fixed
Single parent
Mid-parent
Offspring-parent regression analysis
When n = 1
When n = 1
When n = 2
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