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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Plant Sci. | doi: 10.3389/fpls.2019.01074

Phylogeny of Hawaiian Melicope (Rutaceae): RAD-Seq resolves species relationships and reveals ancient introgression

  • 1Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-Universität Göttingen, Germany
  • 2National Tropical Botanical Garden, United States
  • 3Department of Ecology and Evolutionary Biology, Yale University, United States
  • 4Department of Ecology, Evolution, and Environmental Biology, Columbia University, United States
  • 5Department of Botany, Smithsonian Institution, United States

Hawaiian Melicope are one of the major adaptive radiations of the Hawaiian Islands comprising 54 endemic species. The lineage is monophyletic with an estimated crown age predating the rise of the current high islands. Phylogenetic inference based on Sanger sequencing has not been sufficient to resolve species or deeper level relationships. Here we apply Restriction-site Associated DNA sequencing (RAD-seq) to the lineage to infer phylogenetic relationships. We employ Quartet Sampling to assess information content, statistical support, and to quantify discordance as well as partitioned ABBA-BABA tests to uncover evidence of introgression. Our new results drastically improved resolution of relationships within Hawaiian Melicope. The lineage is divided into five fully supported main clades, two of which correspond to morphologically circumscribed infrageneric groups. We provide evidence for both ancestral and current hybridization events. We confirm the necessity for a taxonomic revision of the Melicope section Pelea, as well as a re-evaluation of several species complexes by combining genomic and morphological data.

Keywords: adaptive radiation, D-statistics, Hawaiian flora, Introgression, Marquesas Islands, Quartet sampling, RAD-seq, Rutaceae

Received: 24 Apr 2019; Accepted: 07 Aug 2019.

Copyright: © 2019 Paetzold, Wood, Eaton, Wagner and Appelhans. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Mx. Claudia Paetzold, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-Universität Göttingen, Department of Systematics, Biodiversity and Evolution of Plants, Goettingen, 37075, Lower Saxony, Germany, claudia.paetzold@uni-goettingen.de