Evolution of Symbiodiniaceae genes; (A) the number of homologous protein sets is shown above each node and branch and represents those that are shared among or specific to S1, Ev, S2, and/or Po; number of protein sets that are exclusive to Ev, to S1, to Ev + Po, to S2 + S1, and to S2 + S1 + Po were highlighted, and (B) enriched gene ontology (GO) terms for genes in the five distinct groups relative to all GO terms in the corresponding taxa, arranged in decreasing order of significance from top to bottom within the categories: Cellular Component, Biological Process, and Molecular Function.