Figure 5.

Phylogenetic tree of the dystrophin/dystrobrevin/dystrotelin superfamily. This summary tree reflects our best estimate of the evolutionary relationships between members of this protein family. Large coloured boxes – major families within the superfamily (the broken line reflects the tentativeness of the orthology of DAHs and dystrotelins). Lighter boxes – vertebrate family members. Asterisks – sequences described for the first time in this study. Black circle – unresolved point of divergence between dystrophins, dystrobrevins and dystrotelins. Phylogenetic distance is represented by the horizontal axis only. This summary tree has been compiled using a selection of smaller trees based on longer sequences (which are each only applicable to the local branches) and a large tree based on the short sequences which are alignable between all family members. A selection of methods has been used, and the tree shown reflects the consensus topology, using distances from neighbour-joining trees. The only points of equivocation were the position of the cyclostome dystrophin/utrophin branch, the position of the γ-dystrobrevin branch, and the relationship between the DAHs and dystrotelins; the former two are described at length in the text; the latter is left as a trichotomy. Letters A-L are a key to events described in our Conclusions. Schematic diagrams at left and right show domain structures of respective proteins, not drawn to scale.