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Abstract Detail

Systematics Section

Morgan, David R. [1], Holland, Blake [1].

Systematics of Symphyotrichinae (Asteraceae: Astereae): Disagreements between two nuclear regions indicate complex relationships between Psilactis and Symphyotrichum.

We studied relationships among the members of Symphyotrichinae using sequence data from two nuclear regions: the ITS+ETS and the 5S rRNA spacer. Sequence data from the two regions were analyzed separately using parsimony, along with bootstrap and decay analyses. Data from both ITS+ETS and 5S spacers identified a well-supported “Symphyotrichum clade” composed entirely of species of Symphyotrichum, but there were also a number of disagreements between the two sets of results. Further analysis identified three of these incongruences as well supported. The first well-supported incongruence involved a small group of Mexican Symphyotrichum species. This group was placed in Psilactis by the ITS+ETS results, but the 5S spacer data placed it in the Symphyotrichum clade. The second incongruence involved a group of species from Symphyotrichum subgenus Virgulus. This group was placed in the Symphyotrichum clade by ITS+ETS evidence but with Psilactis by 5S spacer data. The third incongruence involved Symphyotrichum tenuifolium, which was a close relative of S. subulatum in the ITS+ETS results and of Ampelaster in the 5S results. The occurrence of these well-supported incongruences suggests possible reticulate evolution in the affected species and groups.

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1 - University of West Georgia, Biology, Carrollton, Georgia, 30118, U.S.A.

reticulate evolution
molecular systematics
nuclear ribosomal DNA.

Presentation Type: Oral Paper:Papers for Sections
Session: 36
Location: 556A/Convention Center
Date: Tuesday, August 3rd, 2010
Time: 3:00 PM
Number: 36009
Abstract ID:68

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