Selected GO categories over-represented among genes predicted to be under positive selection.

Shown are numbers of PSGs and of all genes (out of 16,529 considered) assigned to each category or a descendant category, and one-sided (nominal) P-values from the Mann-Whitney U (MWU) and Fisher's exact (FET) tests (see Methods). Only the 400 PSGs from the test for selection on any branch of the phylogeny are considered here. Note that the MWU P -values do not consider whether or not each gene is predicted to be a PSG, but instead indicate the degree to which the LRT P -values for the genes of each category are shifted toward small values. Consequently, classes of genes experiencing relaxation of constraint but not positive selection may obtain small MWU P -values. In contrast, the FET P -values indicate over-representation of the identified PSGs within each category (or, equivalently, over-representation of each category among the PSGs). Bold indicates significance after a conservative correction for multiple testing (FWER<0.05, Holm correction). The two categories with asterisks are enriched for long genes (see Text S1). Only selected categories FWER-significant P -values under the MWU test are shown; see Table S2 for a complete list.