[R] Mixed-effects models / heterogeneous covariances

From: Lutz Ph. Breitling <lutz.breitling_at_gmail.com>
Date: Wed 01 Feb 2006 - 05:22:52 EST


Dear R-list,

maybe someone can help me with the following mixed-effects models problem, as I am unable to figure it out with the 'nlme-bible'.

I would like to fit (in R, obviously) a so-called animal model (google e. g. "Heritability and genetic constraints of life-history" by Pettay et al.) to estimate the variance component that is due to genetic effects. The covariances of the genetic random effects between observations are given by the different degrees of relatedness between the individuals examined. (I find it difficult to explain, but Pettay et al. describe it nicely in their methods section...)

Is there any straight-forward way to fit such a model with R? I first thought I could handle it somehow with nlme's correlation structures, but these within-group structures are quite a different thing, right?

Any suggestions would be highly appreciated-

--
Lutz Ph. Breitling
University of Leeds/UK

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Received on Wed Feb 01 05:31:32 2006

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