Table 1.

Likelihood Ratio Tests of Selective Pressures on Bat Tas1r2 Gene.

Models	ω (dN/dS)	ln La	npb	Models Compared	2Δ(ln L)c	P Valuesd
Dataset I: 39 sequences (all except vampire bats)
A. All branches have   one ω	ω = 0.192	−6223.77	78
B. All branches have the same ω = 1	ω = 1	−6485.21	77	B vs. A	522.88	1.0 × 10−115
C. Branches in yellow have ω1, branches   in blue have ω2, and branches a, b, c, and d each has its own ω	ω1 = 0.183, ω2 = 0.205	−6211.42	84
D. Branches in yellow have ω1,   branches in blue have ω2 = ω1, and branches a, b, c, and d each has its own ω	ω1 = ω2 = 0.196	−6211.42	83	D vs. C	0.64	0.422
E. Each branch has its own ω	Variable ω by branch	−6189.76	153	A vs. E	68.02	0.703
Dataset II: 40 sequences (dataset I plus the ancestral sequence of vampire bats)
F. All branches have the same ω	ω = 0.211	−6575.83	80
G. Branch e (ancestral to   vampire bats) has ω2 and other branches have ω1	ω1 = 0.192, ω2 = 0.994	−6559.21	81	F vs. G	33.23	8.2 × 10−9
H. Branch e has ω2 = 1 and   other branches have ω1	ω1 = 0.192, ω2 = 1	−6223.77	79	H vs. G	0	1
Dataset III: 42 sequences (all bats, after removing gaps in pseudogenes)
I. Branch e and branches connecting   the three vampire bats have ω2 whereas other branches have ω1	ω1 = 0.193, ω2 = 0.424	−6158.29	85
J. Branch e has ω3, branches connecting   the three vampire bats have ω2, and other branches have ω1	ω1 = 0.193, ω2 = 0.393, ω3 = 911.06	−6156.79	86	I vs. J	3.00	0.083

^aThe natural logarithm of the likelihood value.

^bNumber of parameters.

^cTwice the difference in ln L between the two models compared.

^dP values lower than 0.05 are shown in bold.