The phylogenetic tree showing sequence substitution pattern of each primate lineage. The numbers of non-synonymous and synonymous substitutions (N/S) and the amino-acid insertions-deletions are labeled for each lineage. The labeled "8/0" between HUM-1and HUM-2 only represents the total N/S sites in the human population, and the labeled "7aa-del 2/1" between CHP-1 and CHP-2 just represents the sequence difference between the within-species copies. Using marmoset sequence as outgroup, all internal node sequences were inferred by PAML. The lineages showing Ka/Ks ratios significantly larger than one are denoted by '*' (p < 0.05) or '**' (p < 0.01). The solid bars indicate the duplication events, and the dashed bar on the chimpanzee lineage indicates the uncertainty of number of duplication events. The lineages leading to humans and chimpanzees since the most recent common ancestor of Catarrhines (node E) are shown in thick lines. For the abbreviations of the primate species, refer to table 1.