Re: heritability estimation

Dear Derek,
I don't follow your email.
1)
"I have calculated the heritability of a trait from a half-sib design using the standard formula, the animal model using asreml in SPLUS and the "interactive version" of asreml." Are there 3 methods here (Sire model, Animal mode (Splus version) and Animal model (Standalone ASReml version) or just 2 (SPLUS and Standalone animal models)?
2)
"The first two agree but the second only gives me a value that is one half of what it should be. " Since I don't understand the first sentence I do not know what agrees in the second. But in any case, how can the first 2 agree, when the second is 'half', and was is the 'it'? heritability?
3)
It would help if you cut and pasted the variance components calculated from each run. Then I could see whether there are two or three, and what exactly is different.
4)
The .pin file is correct for the standalone asreml and the model shown.
ASReml-r possibly returns var( t( Agamma, Sigma2) while ASReml standaline returns (.in the .vvp file) var(Avariance, Sigma2) where Avariance is Agamma*Sigma2
[ASReml uses first order apprximations for the rescaling)
5)
From the .vvp file values, its is relatively easy to calculate var(Avariance+Sigma2) and derive the se of heritability then using expressions in the ASReml userguide. However, ASReml-r does not have builtin functions for this.

------------------------
Arthur Gilmour

Retired Principal Research Scientist (Biometrics)

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Received on Thu Jun 18 2009 - 19:58:26 EST