Figure 3

Phylogenetic analysis of Irx genes in metazoans. The represented tree is a maximum-likelihood tree, which has been rooted using the Irx gene from Hydra as outgroup (this should be considered as arbitrary rooting). This tree is based on a multiple alignment that includes the Irx conserved domains. The most important monophyletic groups are indicated in red and the associated numbers are their statistical support values obtained with different methods of phylogenetic reconstruction, as described in Figure 2. Statistical support in the maximum-likelihood analysis for some other internal branches is indicated in black. Only statistical support values >50% are shown except for a few cases. Other internal branches (with statistical support <50%) should be considered unreliable. The black arrow points to the group which is discussed in the main text.