Figure 6From: Expression and phylogenetic analysis of the zic gene family in the evolution and development of metazoansModel of zic gene evolution. (A) gli and glis genes were probably present at the base of the metazoan tree (A, green circle). A duplication event occurred either at the base of the Metazoa (A, blue circle 1) or in the last common ancestor of placozoans/cnidarians/bilaterians (A, blue circle 2), which gave rise to the zic sub-family. According to this phylogeny placozoans probably lost the gli/glis/nkl-like gene(s) (A, orange hexagon). The nkl family radiated prior to the cnidarian and bilaterian divergence (A, magenta square). (B) The Zic 1-3 odd paired conserved (ZOC) domain was present in the common ancestor of the bilaterians and cnidarians, but may have emerged in the placozoan/cnidarian/bilaterian common ancestor (B, red boxes with question mark). The ZF-NC domain probably arose in, or just prior to, the cnidarian/bilaterian common ancestor (B, green box).Back to article page