Rapid birth-and-death evolution of the xenobiotic metabolizing NAT gene family in vertebrates with evidence of adaptive selection

Table 2 Results of PAML analyses for the vertebrate dataset

Data set	2ΔlnL	df	P-value	Proportion of sites with ω > 1 (average ω for these sites)	Positively selected codons^a
All vertebrates ( n = 77)
M1a vs. M2a	15.22	2	P = 0.0005	0.017 (ω = 2.0)
M7 vs. M8	34.89	2	P < 0.0001	0.050 (ω = 1.3)	97*, 98, 104, 286
M0 vs. free ratios	510.67	142	P < 0.0001
Mammals ( n = 55)
M1a vs. M2a	31.27	2	P < 0.0001	0.027 (ω = 2.3)
M7 vs. M8	47.39	2	P < 0.0001	0.066 (ω = 1.6)	97*, 98, 104, 214, 286**
M0 vs. free ratios	265.71	100	P < 0.0001
Primates ( n = 17)
M1a vs. M2a	0	2	P = 1.0	none
M7 vs. M8	0	2	P = 1.0	none
M0 vs. free ratios	36.45	28	P = 0.13

n, number of sequences; 2ΔlnL, twice the log-likelihood difference of the models compared; df, degrees of freedom; P-value, level of significance (P-values < 0.05 are shown in bold).
^a Sites pinpointed to be under positive selection under the selection model with the highest likelihood (M8 for the vertebrate and mammalian datasets) by Bayes Empirical Bayes (BEB) analysis. Only sites with posterior probability greater than 0.95 (*) or 0.99 (**) are shown. Sites are numbered according to the full human coding sequence.

ISSN: 2730-7182