Dear Ineke,
Brian's comments are right.
Under a sire model, it is possible for the intraclass correlation to exceed 0.25 implying a heritability greater than 1. When that happens, ASReml would fail
to fit an animal model because h2 > 1 implies residual variance is negative.
This can happen if there are fixed effects confounded with sire effects,
and for some data structures, when there are maternal effects and/or
family effects. Since your data is a four level discrete scale, this could be contributing to the problem as well.
------------------------
Arthur Gilmour
Retired Principal Research Scientist (Biometrics)
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Received on Sat Sep 11 2009 - 09:07:03 EST
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