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Abstract Detail



Phylogenomics

Konowalik, Kamil [1], Wagner, Florian [1], Tomasello, Salvatore [1], Greiner, Roland [2], Vogt, Robert [3], Oberprieler, Christoph [1].

Scrutinizing homoploid hybrid speciation in the genus Leucanthemum (Compositae, Anthemideae) using species tree reconstruction methods.

The genus Leucanthemum Mill. is a species-rich polyploid complex of southern and central Europe, comprising 41 species with ploidy levels ranging from 2x to 22x. Cloning and sequencing of the external transcribed spacer region of the nuclear ribosomal repeat (nrDNA ETS) for diploids of the genus showed that there are two major ETS ribotypes realised in Leucanthemum, with some of the diploid species fixed for either of the two types and a number of species exhibiting both types, suggesting a homoploid hybrid origin of the latter ones. In order to detect hybridisation in the data set and to pinpoint taxa with higher probabilities of being of hybrid origin compared to others, we used a strategy based on the method described by Yu et al. (2012) for estimating the probability of a gene tree topology within a given phylogenetic network. Having inferred the species tree for 19 diploid Leucanthemum taxa and the outgroup taxa based on gene trees from ten nuclear and plastidal markers, we calculated a ´hybrid index´ for each of the Leucanthemum accessions by (a) describing all possible triplet species trees, (b) pruning of gene trees to produce the corresponding triplet gene trees, (c) calculating the probabilities for hybrid vs. non-hybrid scenarios for a given triplet based on the simultaneous consideration of all ten triplet gene trees, and (d) summing up for each diploid taxon the frequency of its hybrid/non-hybrid interpretation.

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1 - University of Regensburg, Institute of Botany, Universitätsstr. 31, Regensburg, D-93040, Germany
2 - Friedrich-Schiller-University Jena, Institute for Systematic Botany, Philosophenweg 16, Jena, D-07743, Germany
3 - Freie Universität Berlin, Botanic Garden & Botanical Museum Berlin-Dahlem, Königin-Luise-Str. 6-8, Berlin, D-14191, Germany

Keywords:
Polyploidy
Phylogenetics
speciation
gene trees
species tree.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Grand Salon A - D/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 5:30 PM
Number: PPL001
Abstract ID:372
Candidate for Awards:Genetics Section Poster Award


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