Charles Heiser Special Contributed Paper Session
Moody, Michael , Rieseberg, Loren .
Sorting through the chaff, nDNA gene trees for phylogenetic inference and hybrid identification of annual sunflowers (Helianthus sect. Helianthus).
The annual sunflowers (Helianthus Sect. Helianthus) present a formidable challenge for phylogenetic inference because of ancient hybrid speciation, recent introgression, and suspected issues with deep coalescence. We analyzed sequence data from 11 nDNA genes for multiple genotypes of most species of the section to (1) reconstruct the phylogeny of this group, (2) explore the utility of nDNA gene trees for detecting hybrid speciation and introgression; and (3) test a new empirical method of hybrid identification based on the phylogenetic congruence of nDNA gene trees from tightly linked genes. We uncovered considerable topological heterogeneity among gene trees with or without three previously identified hybrid species included in the analyses, as well as a general lack of reciprocal monophyly of species. Nonetheless, partitioned Bayesian analyses provided strong support for the reciprocal monophyly of all species except H. annuus (0.89 PP), the most widespread and abundant annual sunflower. Previous hypotheses of relationships among taxa were generally strongly supported (1.0 PP), except among taxa typically associated with H. annuus, apparently due to the paraphyly of the latter. While the nDNA gene tree analyses provided a useful means for detecting recent hybridization, identification of ancient hybridization was problematic for the two most ancient hybrid species, even when linkage was considered.
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1 - University of Western Australia, Plant Biology, 35 Stirling Highway, Crawley, WA, 6009, Australia
2 - University Of British Columbia, Department Of Botany, 6270 University Blvd, Vancouver, BC, V6T 1Z4, Canada
Helianthus Sect. Helianthus
Presentation Type: Oral Paper:Papers for Topics
Location: Lindell D/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 9:00 AM