Evolutionary tree of vertebrate CCT6 proteins. ML tree of CCT6 proteins from mammals, chicken, and frog (in roman font) and translated sequences of the related pseudogenes from human, mouse, and rat (in bold-italics font). Only one copy of CCT6 was found in chicken and frog. Two copies, CCT6A and CCT6B, were found in all mammals examined, including marsupial (Md) and platypus (Oa). The CCT6 sequences from chicken (Gg) and from the two amphibians Xenopus laevis (Xl) and Xenopus tropicalis (Xt) were used to root the tree. All human, mouse, and rat pseudogenes clustered with the CCT6A sequences. Numbers next to branches indicate percent bootstrap values. Only bootstrap values > 30% are shown. For all species abbreviations see the legend for Figure 2. The scale bar represents the indicated number of substitutions per position for a unit branch length.