Table 2. Parameter estimates and likelihood ratio statistics (2Δl) for bird sodium channel genes.

Models	p	l	Parameter estimates	2Δl	PSSs
M0 (one-ratio)	1	−6494.1	ω = 0.09		None
M1a (neutral)	2	−6407.5	p0 = 0.89 (p1 = 0.11)		Not allowed
			ω0 = 0.06 (ω1 = 1)	0
M2a (selection)	4	−6407.5	p0 = 0.89		None
			p1 = 0.06 (p2 = 0.04)
			ω0 =  = 0.06 (ω1 = 1)
			ω2 = 1
M7 (beta)	2	−6349.7	p = 0.38, q = 2.68	11.6	Not allowed
M8 (beta & ω)	4	−6343.9	p0 = 0.97 (p1 = 0.03)		None
			p = 0.48, q = 4.83
			ωs = 1

Note: Meanings for p, l and 2Δl are the same with those in Table 1 and the same below in Tables 3, 4, 5.