Exon Primed, Intron Crossing (EPIC) markers for evolutionary studies of Ficus and other taxa in the fig family (Moraceae)

Abstract

• Premise of the study: The genus Ficus (fi g trees) comprises ca. 750 species of trees, vines, and stranglers found in tropical forests throughout the world. Fig trees are keystone species in many tropical forests, and their relationship with host-specific wasp pollinators has received much attention, although many questions remain unresolved regarding the levels of host specificity,cospeciation, and the role of hybridization in fig and wasp speciation. We developed exon-primed intron-crossing (EPIC)markers to obtain phylogenetic resolution needed to address these questions. • Methods and Results: Expressed sequence tags (ESTs) from F. elastica were compared to Arabidopsis and Populus genomes to locate introns and to design primers in flanking exons. Primer pairs for 80 EPIC markers were tested in samples from divergent clades within Ficus and the outgroup Poulsenia (Moraceae). • Conclusions: Thirty-one EPIC markers were successfully sequenced across Ficus , and 29 of the markers also amplified in Poulsenia , indicating broad transferability within Moraceae. All of the EPIC markers were polymorphic and showed levels of polymorphism similar to that of the widely used internal transcribed spacer (ITS).