The evolutionary process of PSMD4 -derived region (top panel) and PIP5K1A -derived region (bottom panel) inferred based on the free ratio model of CODEML. Blue and yellow bars marks ancestral branches leading to human and chimp in PSMD4-derived region and PIP5K1A-derived region, respectively. "P" indicates the parental gene. The number like "5.1/3.1" indicates how many nonsynonymous substitutions and synonymous substitutions occur in this branch, while the number in thicker font like "0.66" indicates Ka/Ks. In addition, we mark all branches with Ka/Ks significantly different with one by "a", which means a p of 0~0.05. Considering the small number of substitutions, we also mark those branches with a marginal significance (p of 0.05~0.1) by "b".