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Abstract Detail

Systematics Section

Diazgranados, Mauricio [1], Fauser, Rachel [1], Barber, Janet C. [1].

Insights into the phylogeny of the subtribe Espeletiinae Cuatrec. (Compositae) based on multiple molecular markers: nuclear sequence data, AFLPs and microsatellites.

The high elevation grassland ecosystem of the Northern Andes, known as páramo, is the most diverse ecosystem of the high elevations of the world, and is an ideal system to understand rapid adaptive radiations and speciation mechanisms in sky islands. Frailejones (subtribe Espeletiinae, Asteraceae) exemplify a spectacular radiation in the páramos and provide a potential model system for investigating this phenomenon. The nearly 143 named species are grouped into eight genera: Carramboa (5 spp.), Coespeletia (6 spp.), Espeletia (68 spp.), Espeletiopsis (27 spp.), Libanothamnus (11 spp.), Paramiflos (1 sp.), Ruilopezia (24 spp.) and Tamania (1 sp.). These plants are widely distributed and abundant in the high Andean forest and páramos of Colombia, Venezuela and, to a lesser extent, Ecuador, and the preservation of the páramo ecosystem depends largely on them. Although there have been some previous attempts to reconstruct the evolutionary history of this group based on morphological and molecular data, relationships among genera and species remain largely unresolved. We aim to reveal inter- and infrageneric relationships within Espeletiinae using sequence data, AFLPs and STRs. Recent data from three nuclear regions (ITS, ETS of the 18S26 rDNA and gapC, >3,500 bp), 16 AFLP loci and 9 microsatellite loci are being analyzed. Results show strong support for the monophyly of the subtribe. Rumfordia and Smallanthus appear to be the closest relatives to the group. The phylogeny suggests a geographic structure, with one clade containing only Venezuelan species and another comprising only Colombian species, and internal clades representing geographic complexes. None of the polytypic genera is monophyletic, and the position of the paraphyletic Carramboa supports the proposed origin of the subtribe in Venezuela. Incongruence between the different data sets may be due to hybridization, incomplete lineage sorting in recent radiations, and/or differential tempo in evolution of the DNA markers.

Broader Impacts:
Results from this project will enable a better understanding of rapid speciation processes in the tropical high mountain ecosystems. The resulting phylogeny will inform revision of Espeletiinae taxonomy and will establish a framework to guide current and future studies of these keystone páramo species. The project will develop tools and methodologies that can be applied in other related species. A public website is being developed and a key to species constructed in Lucid3 will also be available online and on DVD. The research involves the active collaboration of the Missouri Botanical Garden, the Smithsonian Institution, Saint Louis University and several institutions in South America (primarily in Colombia and Venezuela). This project is strengthening multinational collaborations and is training undergraduates at the home institution as well as several visiting researchers.

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Related Links:
The Espeletia Project

1 - Saint Louis University, Department of Biology, 3507 Laclede Ave., St. Louis, MO, 63103-2010, USA

Nuclear DNA

Presentation Type: Oral Paper:Papers for Sections
Session: 36
Location: 556A/Convention Center
Date: Tuesday, August 3rd, 2010
Time: 4:15 PM
Number: 36014
Abstract ID:519

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