Figure 1.

The effect of locus frequency, GRR, and overall λ_S on the relative performance (as measured by the expected P-value) of affected relatives vs. unrelated affected individuals. The three rows correspond to three different frequencies for the disease locus: 0.01, 0.001, and 0.0001. λ_S is between 2 and 10. The number of affected individuals is 2000: 1000 sib-pairs, 1000 first-cousin pairs, 1000 second-cousin pairs, 2000 unrelateds, and 2000 unrelated individuals known to have an affected sibling (i.e., unrelateds+).