ABSTRACT This unrooted phylogenetic tree of the myosin superfamily (see insert) is derived from an alignment of 139 members of the myosin superfamily. The alignment compared the core motor domains (equivalent to residues 88-780 of chicken skeletal myosin II) of each myosin, using distance matrix analysis performed with the Clustal-W package. The exceptions, shown with a dotted line, are SsVIIa, which is a partial sequence as reported in the databases, and Hs MysPDZ. The latter is reported as a complete coding sequence but has a truncated N terminus starting some 52 residues into the core motor region (i.e. residue 140 of chicken skeletal myosin II). These shorter sequences have no significant effect on the branching order of the rest of the tree.