Table 1.

Comparisons of $F_{ST}$ on the X chromosome and autosomes

Populations	${\mathit{F}}_{\mathit{ST}}^{\mathit{A}}$	${\mathit{F}}_{\mathit{ST}}^{\mathit{X}}$	Q
CE-AF	0.004	0.005	0.700
CE-HG	0.053	0.057	0.911
BA-SP	0.008	0.032	0.237
BA-AF	0.025	0.030	0.826
BA-HG	0.031	0.035	0.872

The quantity Q compares genetic differentiation, calculated from $F_{ST}$, on the X chromosome and autosomes. For an ideal population with no changes in effective size, Q is expected to be 3/4 (Materials and Methods). Notably, Q is close to 3/4 for the CE-AF comparisons, but it is considerably lower for the BA-SP comparisons.