Positive selection in the different lineages of genes of heme biosynthesis pathway.

aTwice the difference between the log likelihood of M0 (one ratio) and two ratio model.bp-value p(χ2) of the likelihood ratio test.cFor the branch-site model A, the following four classes are demarcated to each amino acid: class 0 with 01 but background 01 but background ω1 = 1. p0 is the proportion of codons with 01 but with background ω0 in class 2a; p2b is the proportion of codons with foreground ω2>1 but with background ω1 = 1 in class 2b.dBayes empirical Bayes (BEB) is used to calculate the posterior probabilities to identify the sites (amino acid residues) under positive selection (higher than 95%). The sites are indexed by the amino acids of the site in the human sequence (ALAS1, PBGS, UROD).