Figure 2 .

Quantile–quantile plots of P-values to test the null hypothesis of no pleiotropy. Sample size was 1000 with four equally correlated traits $\left(\rho =0.2\text{ or }0.8\right).$ All but one $\beta$ was zero; the nonzero $\beta$ was chosen such that there was either 30% or 90% power to detect its marginal effect using $\alpha =\mathrm{0.001.}$ A total of 10,000 simulations were performed.