Phylogenomic analyses reveal extensive gene flow within the magic flowers (Achimenes)

Abstract

Premise of the Study: The Neotropical Gesneriaceae is a lineage known for its colorful and diverse flowers, as well as an extensive history of intra- and intergeneric hybridization, particularly among Achimenes (the magic flowers) and other members of subtribe Gloxiniinae. Despite numerous studies seeking to elucidate the evolutionary relationships of these lineages, relatively few have sought to infer specific patterns of gene flow despite evidence of widespread hybridization. Methods: To explore the utility of phylogenomic data for reassessing phylogenetic relationships and inferring patterns of gene flow among species of Achimenes, we sequenced 12 transcriptomes. We used a variety of methods to infer the species tree, examine gene tree discordance, and infer patterns of gene flow. Key Results: Phylogenomic analyses resolve clade relationships at the crown of the lineage with strong support. In contrast to previous analyses, we recovered strong support for several new relationships despite a significant amount of gene tree discordance. We present evidence for at least two introgression events between two species pairs that share pollinators, and suggest that the species status of Achimenes admirabilis be reexamined. Conclusions: Our study demonstrates the utility of transcriptome data for phylogenomic analyses, and inferring patterns of gene flow despite gene tree discordance. Moreover, these data provide another example of prevalent interspecific gene flow among Neotropical plants that share pollinators.