High degree of conservation in the homeo- and acidic carboxy-terminal domains in evolution.

(A) ClustalW alignment of the 60 amino acid homeodomain sequences. The MIXL homeodomain shows 66% identity to that of XenopusMix.1. Residues constituting the 3 helical motifs are denoted. Note the high identity in the amino-terminal arm and helix 3 responsible for DNA binding. (B) Homology in the carboxy-terminal acidic domain. The highly conserved SxxSD/E and WEE motifs are denoted.