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Abstract Detail


Systematics Section

Selliah, Sugirthini [1], Brouillet, Luc [2].

Phylogeny and biogeography of the intracontinally disjunct North American eurybioid asters (Asteraceae: Astereae) inferred from combined ribosomal and plastid DNA sequences, with insights from low-copy nuclear DNA data.

The eurybioid asters comprise four North American genera Oreostemma, Herrickia, Eurybia and Triniteurybia. Earlier nrDNA-based studies showed that this group is sister to Symphyotrichinae and paraphyletic to Macharantherinae, whereas species relationships were only partly resolved and poorly supported, and it proved impossible to ascertain the relationships of polyploids. The current analysis is restricted to diploid taxa. In an attempt to increase resolution and support, we investigated non-coding regions from cpDNA (trnC-ycf6, trnS-G, trnL-F) as well as part of the nuclear, low-copy gene CNGC4, in addition to ITS and ETS nrDNA data. Both separate and combined analyses of cp and nrDNA data were performed using Maximum parsimony and Bayesian analyses; the combined analyses are presented here. The CNGC4 analysis is presented separately, mostly to provide further insights into the evolution of the group. For biogeographic analyses, DIVA and LaGrange were used on the combined dataset. The combined phylogenetic analyses brought more resolution and support than the phylogenies based on nrDNA data, confirming the following relationships: Oreostemma (Herrickia (Herrickia kingii (Eurybia (Triniteurybia-Machaerantherinae))). Herrickia is confirmed as paraphyletic, with H. kingii well supported as sister to the crown eurybioids. Within Eurybia, the western E. integrifolia is sister to the whole genus, followed by the divergence of the Florida panhandle E. eryngiifolia. Next are two western species, E. sibirica and E. radulina, the latter sister to an eastern North American clade. Both biogeographic analyses confirmed a radiation in the western United States for the eurybioids, with two independent migrations to eastern North America within Eurybia. The group evolution was considered recent, probably not older than Pliocene in age and therefore strongly influenced by the Pleistocene glaciations. The CNGC4 topology showed a high level of incomplete lineage sorting, which would support the hypothesis that the group is of recent origin.


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1 - Universite de Montreal, Institut de recherche en biologie vegetale, 4101 Sherbrooke St. E, Montreal, Quebec, H1X 2B2, Canada
2 - Université de Montréal, Institut de recherche en biologie végétale, 4101 rue Sherbrooke est, Montréal, Québec, H1X 2B2, Canada

Keywords:
molecular phylogeny
Biogeography
Astereae
Asteraceae
Eurybia
Triniteurybia
Oreostemma
Herrickia
North America
cpDNA
nrDNA
CNGC4.

Presentation Type: Oral Paper:Papers for BSA Sections
Session: 63
Location: Cottonwood D/Snowbird Center
Date: Wednesday, July 29th, 2009
Time: 10:45 AM
Number: 63005
Abstract ID:99


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