Dicyemid genes cloned in this study. The entire protein-encoding (open box) domains and the functional domains (ZF, zinc finger domain, black; PD, paired box, gray; HD, homeodomain, hatched) are drawn proportionally. Positions of introns are indicated by open triangles. The number above each open triangle indicates the size (in nucleotides) of the intron at that position. actin2 and ATP synthase lack introns. Scale bar, 100 aa.