Table 2. Parameters estimates and log likelihood values for branch-site M1a, MA and restricted MA model.

Model	Parameters			lnL
M1a	ω0 = 0.04651	p0 = 0.86743		-11 046.650097
Relaxed branch-site test null model	ω1 = 1.00000	p1 = 0.13257
Restricted MA (ω2 = 1 fixed)	ω0 =0.04520	ω2 = 1.000		-11 039.638028
Strict branch-site test null model	p0 = 0.82646	p1 = 0.12587	(p2a + p2b) = 0.04767
MA	ω0 = 0.04596	ω2 = 50.90099		-11 032.575669
Alternative model	p0 = 0.84965	p1 = 0.12542	(p2a + p2b) = 0.02493

Lnl = log likelihood; ω0 = dN/dS values for sites with 0 < ω < 1; ω1 = dN/dS values fixed to 1; ω2 = dN/dS values for sites with ω > 1, which corresponds only to sites in the foreground branch.