Multiple alignment of aa sequences corresponding to Zic ZF and flanking regions. Dots represent aa residues identical to those in the top lines (Homo _ZIC2). Dashes indicate artificial spaces inserted by the alignment program. Horizontal shaded lines indicate the Dicyema Zic sequences. Vertical shaded lines indicate the positions of cysteine and histidine residues in the C2H2 motif. Labels above the top lines indicate subregions (ZFNC, Zinc finger N-terminal conserved region; 1–5, C2H2 ZF motif 1–5). Open box labeled with (A)* indicates the position of the bilaterian-specific intron (A-intron) , where the exon-intron boundaries for the Halocynthia, Octopus, and Dugesia sequences have not yet been clarified. Cnidarian Zic genes (Nematostella, Scolionema, and Hydra) lack the intron in this position. Bottom parallel lines indicate the region subjected to the aa substitution rate analysis. Bottom underlines and parallel lines indicate the region used for the NJ tree analysis.