Figure 1.

Phylogenetic tree of the D. discoideum MADS-box-containing proteins. The amino acid sequences of the MADS-box region from MEF2 and SRF proteins from vertebrates (H. sapiens, X. laevis, G. gallus), invertebrate (D. melanogaster, A. franciscana) animals, fungi (S. cerevisiae) and amoeba (E. histolytica) were compared to those of the four D. discoideum MADS-box containing proteins (SrfA, B, C and D) using the ClustalW program at the online Biology Work Bench facility from the San Diego Supercomputer Center (http://workbench.sdsc.edu). Phylogenetic trees were determined using the neighbor-joining method and the ClustalX program. A random generator seed of 111 was used, and 1000 bootstrap trials were calculated. The number of times that each branch was obtained is indicated at the base of each branch. The tree was drawn using the NJplot program. The evolutionary distance scale, calculated as a fraction of amino acid changes, is indicated at the left lower corner of the figure.