[R-sig-ME] animal model: calculating heritability and evolvability from sire effects

[Pierre B. de Villemereuil]

Hi !

Concerning the 4 coefficient : you say the additive variance is 
estimated within the full-sibs of the same sire. Is that to say 
offspring of the same sire descent as well from the same dam ? In that 
case (same father and same mother), then the relationship coefficient is 
of 1/2 (2 * coefficient of coancestry of 1/4). So, I think (but I can be 
wrong) the coefficient should be 2.

If each individual descent from a different mother, then kinship is 1/4. 
So the coefficient of 4 is correct.

When estimating the heritability of a binomial trait, you have to keep 
the residual variance in the total variance. Just add the 'link 
variance' (say Vlink) such as :
h² = Va / (Va + Vr + Vlink)    (Vlink is pi²/3 for logit link and 1 for 
probit link)

Cheers,
Pierre.

Le 21/12/2011 12:18, Szymek Drobniak a écrit :
> Hi,
>
> both your code and the way you calculate VA using sire variance seems
> fine. In lmer residual variance is fixed as it assumes fixed
> relationship between variance and mean in binomial data so I'm not
> sure if simply putting this variance in your formula solves the
> problem. In MCMCglmm residual variance quantifies overdispersion so as
> far as I know here it's just a matter of substituting gaussian to
> multinomial2.
>
> Cheers,
> sz.
>
> --
> Szymon Drobniak || Population Ecology Group
> Institute of Environmental Sciences, Jagiellonian University
> ul. Gronostajowa 7, 30-387 Kraków, POLAND
> tel.: +48 12 664 51 79 fax: +48 12 664 69 12
>
> www.eko.uj.edu.pl/drobniak
>
> _______________________________________________
> R-sig-mixed-models at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-sig-mixed-models