Identification of positively selected genes in two seagrass species and their last common ancestor. (A) Phylogenetic tree of ten plant species among which the molecular evolution of orthologous gene sequences has been analyzed. Positive selection in seagrass evolution has been tested for each of the three highlighted branches Po, Zm and LCA. Divergence times have been obtained from [34, 76–80] and the timetree database . (B) Term cloud of over-represented GeneOntology (GO) terms of positively selected genes compared to all tested genes. For each of the three tested branches, enriched GO terms were determined using all other tested genes as a reference as indicated by the different colors. The size of the GO terms is proportional to the p-value obtained in the enrichment test. This procedure creates a representation similar to sequence logos , showing enriched annotation terms instead of sequence conservation patterns. A tabular representation of the enriched GO terms can be found in Additional File 5.