Table 1. Summary of a likelihood ratio test using PAML for positive selection in the SnTox1 gene.

Model pairs	dN/dS	Log likelihood (l)a	P b	Positively selected codons c	Posterior prob.
M1a (nearlyneutral)	0.52	−553.98		48	0.975
M2a (selection)	4.49	−546.04**		68	0.978
M1a/M2a LRT	<0.001			72	0.997
M7 (beta)	0.50	−554.07		106	0.974
M8 (beta & ω)	4.49	−546.127**
M7/M8 LRT	<0.001

^aAsterisks indicate which model resulted in a statistically higher likelihood score for the SnTox1 codon alignment.

^bP-value for the likelihood ratio test (LRT) between the log-likelihoods of comparable models. In both cases the null hypothesis is rejected in favor of the selection model.

^cSpecific codons within the amino acid sequence were tested for positive selection. Positively selected codons with a Bayes Empirical Bayes posterior probability higher than 0.95 are listed on the right half of the table [78].