Table 2.

False Positive Rates under Very Low Divergence.

No. loci	2	10	100	1,000
False positive rate (mixture)	0.01	0.05	0.11	0.02
False positive rate (${\chi }_1^2$)	0.01	0.02	0.05	0.01
Proportion of zero LRTs	0.25	0.12	0.34	0.52

Note.—False positive rates of LRTs for migration rate are computed when the mixture distribution or an original ${\chi }_1^2$ are considered as a null distribution. The proportions of zero values of LRTs are computed as well. The true simulation model is the 2-population isolation models with ${\theta }_1={\theta }_2={\theta }_a=5$ and $T_S={10}^{-6}$, respectively. The number of loci varies from 2 to 1,000, and two gene copies are simulated from each population.