Reconstructing the phylogeny of figs (Ficus, Moraceae) to reveal the history of the fig pollination mutualism

Figs (Ficus, Moraceae) constitute one of the largest genera of flowering plants with ca. 750 species worldwide. While the extraordinary mutualism between figs and their pollinating wasps has received attention for decades, we are only just beginning to reconstruct the phylogeny of both partners, a necessary framework for addressing a variety of questions concerning the evolution of mutualism. Here, we present phylogenetic analyses of 100 species of Ficus, representing all subgenera, sixteen out of nineteen sections, and two outgroups, using three nuclear markers. We explore the utility of the single copy nuclear encoded glyceraldehyde-3-phosphate dehydrogenase gene (G3pdh) for phylogeny reconstruction in Ficus, and evaluate infrageneric relationships based on G3pdh DNA sequences in combination with the nuclear ribosomal internal and external transcribed spacers (ITS and ETS). The G3pdh gene provides limited resolution within Ficus, but increases the proportion of well-supported clades when combined with ITS and ETS. Of the six subgenera traditionally recognized based on morphology and distribution patterns, only subgenus Sycidium is supported as monophyletic. We identify fifteen clades within Ficus, but the branching order of the early lineages of Ficus and some of the internal branches are not well supported and should be considered uncertain at present.