1.5, 2.0, 2.5, and 3.0) under the dominant model for both loci and the MAF for gene h = 0.30. The required sample sizes were 717, 754, and 795 for Rgh = 2.0, 436, 464, and 496 for Rgh = 2.5 and 323, 347, and 375 for Rgh = 3.0 under these three respective sets of parameters when the MAF of gene g is 0.30. Therefore, our study appears to provide sufficient sample sizes to detect an Rgh ≥ 2.0 under all three sets of parameters for the AA sample (~ 930 sibpairs) and the pooled sample (~ 1260 sibpairs), using the case-sibling design as the reference.
