Phylogenetic tree. Alignment of the motor domain of representative myosins and all Arabidopsis myosins was done in Megalign by the CLUSTAL method and a phylogenetic tree was generated using the bootstrap method with a heuristic search of the PAUP 4.0b6 program. The myosin groups, as defined by Hodge and Cope  and Yamashita et al. , are identified on the right in roman numerals. Myosins from the following organisms were used: Ac, Acanthamoeba castellani; Acl, Acetabularia cliftoni; At, Arabidopsis thaliana; Cc, Chara corallina, Ha, Helianthus annuus; Zm, Zea mays; Bt, Bos taurus; Mm, Mus musculus; Ce, Caenorhabditis elegans; Dm, Drosophila melanogaster; Rn, Rattus norvegicus; Sc, Saccharomyces cerevisiae; Hs, Homo sapiens; Dd, Dictyostelium discoideum; Lp, Limulus polyphemus; En, Emericella nidulans; Pg, Pyricularia grisea; Pf, Plasmodium falciparum; and Tg, Toxoplasma gondii. The number at the branches indicates the number of times the dichotomy was supported out of 100 bootstrap tries.