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*To*: asreml@chiswick.anprod.csiro.au*Subject*: RE SE's for boundary fixed parameters*From*: Bruce Southey <bsouthey@bigfoot.com>*Date*: Thu, 24 Feb 2000 08:20:42 -0600*Reply-To*: bsouthey@bigfoot.com*Sender*: asreml-owner@lamb.chiswick.anprod.csiro.au

Hi, Following up Arthur's comments, what is the log likelihood with and without the additive genetic variance? The difference is probably very small. Note that the difference is not distributed Chi-squared but probably a mixture of Chi-squared. With a variance component on the boundary condition, I doubt that SE are valid. But, I don't remember my math stats about this and relates to the conditions required. Given your comments, it does not sound that you should be fitting this model. Basically, you don't have sufficient information to make any conclusion about additive genetic variance. What would be informative is to profile the likelihood with respect to the additive and permanent variance components. I think that you would see that this is rather flat with respect to the additive genetic variance. If so, then you are best to just to fit animal as a random effect. This causes a bias and, if I recall correctly, John James gave a paper about ignoring repeated records in an animal model at one of the AAABG meeting around 1990. If you have a suitable pedigree structure, you could try a parent-offspring regression or sire-dam model etc. Best of luck, Bruce Southey -- Asreml mailinglist archive: http://www.chiswick.anprod.csiro.au/lists/asreml

**Follow-Ups**:**Re: RE SE's for boundary fixed parameters***From:*Kim Bunter <kbunter@metz.une.edu.au>

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