Evolutionary trees of CCT proteins. (a) Maximum-likelihood evolutionary tree of all human chaperonin-like proteins, including CCT monomers, MKKS, BBS10, BBS12 and the two members, CCT8L1 and CCT8L2, of the newly defined CCT8L class. Numbers associated with each branch indicate bootstrap support from 100 replicates. Tree rooted by the archaeal thermosome alpha subunit of Sulfolobus solfataricus (Ss_ThsA). (b) Bayesian evolutionary tree of the same sequences shown in (a). The numbers assigned to each branch indicate posterior probabilities. Tree rooted by the thermosome alpha subunit of Thermoplasma acidophilum (Ta_ThsA). The scale bars represent the indicated number of substitutions per position for a unit branch length.