Miocene–Pliocene speciation, introgression, and migration of Patis and Ptilagrostis (Poaceae: Stipeae)

• Published in: Molecular Phylogenetics and Evolution
• Main Authors: Romaschenko, Kostyantyn, Garcia-Jacas, Núria, Peterson, Paul M., Soreng, Robert J., Vilatersana, Roser, Susanna de la Serna, Alfonso
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2014
• Subjects: At103; Biogeography; Classification; Low copy nuclear DNA sequences; Patis; Phylogeny; Atherton; Bering Land Bridge
• Online Access: http://hdl.handle.net/10261/109901; https://doi.org/10.1016/j.ympev.2013.09.018

16 p., gráf., tablas Genetic interchange between American and Eurasian species is fundamental to our understanding of the biogeographical patterns, and we make a first attempt to reconstruct the evolutionary events in East Asia that lead to the origin and dispersal of two genera, Patis and Ptilagrostis. We conducted a molecular phylogenetic study of 78 species in the tribe Stipeae using four plastid DNA sequences (ndhF, rpl32-trnL, rps16-trnK, and rps16 intron) and two nuclear DNA sequences (ITS and At103). We use single copy nDNA gene At103 for the first time in the grasses to elucidate the evolutionary history among members of the Stipeae. Ampelodesmos, Hesperostipa, Oryzopsis, Pappostipa, Patis, and Stipa are found to be of multiple origins. Our phylograms reveal conflicting positions for Ptilagrostis alpina and Pt. porteri that form a clade with Patis coreana, P. obtusa, and P. racemosa in the combined plastid tree but are aligned with other members of Ptilagrostis in the ITS tree. We hypothesize that Ptilagrostis still retains the nucleotype of an extinct genus which transited the Bering land bridge from American origins in the late Miocene (minimum 7.35–6.37 mya) followed by hybridization and two plastid capture events with a Trikeraia-like taxon (7.96 mya) and para-Patis (between 5.32 and 3.76 mya). Ptilagrostis porteri and Patis racemosa then migrated to continental North America 1.7–2.9 mya and 4.3–5.3 mya, respectively. This project was funded by the Restricted Endowment Fund, the Scholarly Studies Program, Research Opportunities, Atherton Seidell Foundation, Biodiversity Surveys and Inventories Program, National Museum of Natural History-Small Grants, and Laboratory of Analytical Biology (LAB) all part of the Smithsonian Institution. We thank the National Geographic Society Committee for Research and Exploration (Grant Number 8087-06) for field and laboratory support and the Fulbright Scholar Program to KR for a research visit to the Smithsonian Institution. Peer reviewed