Table 1.

PIPSL was under positive selection in the primate ancestor

^aA Fisher’s exact test was used to test the null hypothesis of equal rates of synonymous and nonsynonymous changes on the ancestral PIPSL branch.

^bThe values n, s, N, and S were computed by the modified Nei-Gojobori (NG) method (Zhang et al. 1998).

^cMore conservative estimates by the original NG method are in parentheses.

^dA Fisher’s exact test was used to test the hypothesis of positive selection followed by purifying selection (episodic evolution); the null hypothesis predicts equal rate ratios of n/s between the ancestral branch and descendant lineages.