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Abstract Detail


Systematics Section/ASPT

Toro-Nunez, Oscar [1], Mort, Mark [1].

Phylogenetic relationships inside the tribe Schizopetalae (Brassicaceae) based on nrDNA and cpDNA regions: evolutionary insights from an endemic lineage to Atacama Desert (Chile).

The tribe Schizopetalae comprises two small genera of Brassicaceae, Schizopetalon (10 spp) and Mathewsia (9 spp), which are endemic from southern Peru to Central Chile and the Andes of Argentina. These genera are characterized by their contrasting habits (Schizopetalon - annual, Mathewsia - perennial) and the occurrence of most of their species across the dry coast and Andes of southern Atacama Desert. These characteristics make them suitable for evolutionary studies of adaptation and diversification across the diverse gradient of arid environments in this desert. However, there has been no focused molecular phylogenetic study in either genus. We conducted phylogenetic analyses to assess monophyly and elucidate the phylogenetic relationships within each genus. Separate nuclear (i.e. nrDNA ITS and ETS) and cpDNA (i.e. psbA-trnH, trnQ-rpl16, atpI-atpH, and rps16 intron) data sets were assembled, from a total of 32 individuals representing 17 species (~90% of total taxa). Our results suggest that Schizopetalon is monophyletic but relationships among species are in general weakly supported. In contrast, Mathewsia is not resolved as monophyletic because a species from the high Andes, M. nivea, is not recovered in the Mathewsia + Schizopetalon clade. In both genera, species were placed in groups more associated to areas of geographic distribution than morphological similarity. Also, analyses showed polyphyletic species and strong topological incongruence between nrDNA and cpDNA data sets, suggesting rapid diversification and hybridization events.

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1 - University Of Kansas, Ecology and Evolutionary Biology & Biodiversity Institute, 1200 Sunnyside Avenue, Lawrence, KS, 66045, USA

Keywords:
Schizopetalon
Mathewsia
Brassicaceae
Atacama Desert
cpDNA
nrDNA.

Presentation Type: Oral Paper:Papers for Sections
Session: 18
Location: Franklin A/Hyatt
Date: Monday, July 9th, 2012
Time: 5:00 PM
Number: 18014
Abstract ID:386


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