FIGURE 1.

Box plots of ${\widehat{h}}^2$ , estimated from the linear mixed-effect model (Eq. 4) against δ _causal . The true heritability of the phenotype is h ² = 0.5. The minor allele frequencies p _causal = p _tested = 0.2 and 10,000 independent replicates of phenotypes and genotypes for 65 sibling pairs were simulated for each δ _causal value. The empirical type 1 error rates are shown in Figure 3 as black squares.