Re: Boundary problems

Dear Tuomas,

In an animal model, it is not unusual for the maternal effect to be on the
boundary.

If it is on the boundary for a univariate model, then it will also be on
the boundary in a bivariate model.

If there is no depth of pedigree (i.e. you have no pedigree on the
parents), it might be interesting
to fit the equivalent Sire Dam model.

pcsize ~ mu block ucsize !r sire dam

This should give two components but with the dam component smaller than
the sire component. The id variance from the animal model should be about
4 times the average of the sire and dam components from this model.

The traditional animal model assumes the sire's contribution is purely
genetic but the dam has a genetic
component and a nuturing component. I unerstand for some birds, the
father does the nurturing.

If the trait is late in life relative to the end of maternal nurturing,
then no maternal effect is expected.

Thus maternal effects are expected for birth weight and weaning weight,
but not for yearling weight.

I trust this helps.

May Jesus Christ be gracious to you in 2008,

Arthur Gilmour, His servant .
 
Mixed model regression mapping for QTL detection in experimental crosses.
Computational Statistics and Data Analysis 51:3749-3764 at
http://dx.doi.org/10.1016/j.csda.2006.12.031

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Received on Sat Apr 03 2008 - 14:42:18 EST