Table 1. Test of sites under positive selection by the sliding-windows analysis and by the LRT.

Data	Sliding windows		2Δℓ	2Δℓ
	Statistic a	p-value	(M1a-M2a)	(M7-M8)
Mouse-rat	19	0.096	2.24	2.39
Human-dog	18	0.007**	8.18*	9.08*
Orangutan-cow	23	0.016*	0.35	0.40
Orangutan-macaque	16	0.762	0.00	0.00

^aThe test statistic in the sliding window analysis is the number of windows in which ωˆ>1. The window size is 100 codons, and the offset is 10 codons. In the LRTs, the test statistic 2Δℓ is the log likelihood difference between the null and alternative models.

^*: significance with p<5%.

^**: significance with p<1%.