Figure 7.

Hypothesis for functional evolution of class III HD–Zip genes in vascular plants. Putative origin of new functions are mapped onto the Bayesian gene cladogram based on the phylogram in Figure 5. Clades of angiosperm sequences in the REV and CNA clades are boxed. Circled letters A–F indicate inferred duplications described in the discussion. The broken bars labeled “x” and “y” in the Selaginella clade indicate uncertainty about whether specialization for microphyll vascularization evolved before or after duplication B.