Parsimony analysis of actin and actin-related proteins from apicomplexans and other taxa. Phylogenetic analysis performed using parsimony resulted in groupings that mirrored distance analysis. All major classes of Arp and ALP groups are maintained except for the Arp4 group, which differs slightly from the BioNJ consensus tree in other eukaryotic taxa as well as in the apicomplexans. Relationships were calculated in PAUP*4.01b using the heuristic algorithm and verified by bootstrapping (>100 replicates). Consensus trees were drawn according to the bootstrap 50% majority-rule. Conventional actins were defined as the out-group. Subgroups of Arps and ALPs have been highlighted to define the boundaries between groups. Taxa are defined in Figure 1. Bootstrap values ≥90% are represented by the black nodes ●, values ≥ 75% are represented by the gray nodes , and values ≥50% are denoted by the white nodes ○.