Erratum

After publication of this work [1], regrettably I noted that there was an error in the examples given in Table 1, which was added when the paper was under revision and inadequately checked. A programming error led to incorrect calculations of within-family variances for full-sib families. Formulae and conclusions are unchanged.

Table 1 Comparison of var( ? ^ A 2 ) predicted from the information matrix directly and from the Taylor series approximation*

The correct Table 1 is included here. Table title, headings and footnote are unchanged. Results are changed in columns 4 through 15 and indicated in bold characters.