Abstract Detail

Systematics

Worcester, Lindsey [1], Fishbein, Mark [2].

Phylogeny and Biogeography of the Podostemm Clade, Asclepias L. (Apocynaceae), Based on Three Putative Low Copy Nuclear COSII Loci.

The Podostemma clade includes seven species of milkweeds in the genus Asclepias L. (Apocynaceae). Previous work revealed that the Podostemma clade was well-supported in the plastid phylogeny, though relationships within the clade were poorly resolved. The biogeographic history of this group was also investigated. The Sierra Madre Occidental (SMO) separates closely related milkweed species in the Podostemma clade of Asclepias. In this study, three conserved nuclear loci (COSII) were sequenced for the seven species of Podostemma milkweeds and outgroups. Gene trees for each locus were estimated using maximum likelihood and a species trees was estimated in a multilocus coalescent framework using *BEAST2. Relationships among early diverging species in the Podostemma clade conflict with results from the chloroplast phylogeny, with Asclepias arenaria placed as sister to the remainder of the clade. Relationships among five of species are unresolved due to incongruent patterns of allele sharing between species, likely due to incomplete lineage sorting or introgression. Species do not form eastern and western clades, which does not support a vicariant event involving the SMO.

1 - Oklahoma State University, Department of Plant Biology, Ecology, and Evolution, 301 Physical Sciences, Stillwater, OK, 74078, United States
2 - Oklahoma State University, Plant Biology, Ecology & Evolution, 301 Physical Sciences, Stillwater, OK, 74078, United States

Keywords:
COSII loci
Asclepias
phylogenetics
incomplete lineage sorting (ILS)
Sierra Madre Occidental (SMO)
Podostemma clade.

Presentation Type: Oral Paper
Session: 17, Asterids I part B
Location: 204/Savannah International Trade and Convention Center
Date: Tuesday, August 2nd, 2016
Time: 8:15 AM
Number: 17002
Abstract ID:905
Candidate for Awards:None