Figure 1. Gene groups arranged by level of constraint on coding regions.

Cell invasion, sexual development, transcription factors and CCCH zinc fingers have less constrained protein coding regions than the other groups of genes considered. Elements of the heatmap represent the p-values resulting from testing the alternative hypothesis that proteins in a particular group rank among the least constrained proteins (higher dN/dS) among all proteins with orthologs in 2 particular species. The 15 groups were ranked from the least constrained to the most constrained in each of the 5 cross-species comparisons and the sum of the ranks was determined (Table S2) and used to order the protein groups in the heatmap. Pf-Pv, Pf-Pk, Pf-Py, Pf-Pb and Pf-Pc represent results from comparisons between P. falciparum and P. vivax, P. knowlesi, P. yoelii, P. berghei and P. chabaudii respectively.