Abstract Detail

Recent Topics Posters

Mandracchia, Therese [1], Bryan, Alessandra [1], Boutte, Julien [1], Riser, James [2], Fishbein, Mark [3], Straub, Shannon [1].

Phylogenetics and Species Boundaries of the Dwarf Milkweeds (Asclepias; Apocynaceae).

The dwarf milkweeds of the western United States are four allopatric Asclepias species: A. eastwoodiana, A. ruthiae, A. sanjuanensis, and A. uncialis. These species are highly similar in their morphology and are often identified incorrectly. At times, all four have been considered as belonging to two subspecies of A. uncialis, with A. eastwoodiana, A. ruthiae, and A. sanjuanensis lumped into A. uncialis var. ruthiae. Using a traditional molecular phylogenetics approach, it has been difficult to determine the relationships among these species due to lack of informative characters. In this study, a large DNA sequence data set consisting of plastome sequences produced from thirty-six samples (nine A. ruthiae samples, four A. sanjuanensis samples, thirteen A. uncialis samples, and ten A. eastwoodiana samples) was analyzed in order to assess if phylogenetic signal was present and if the plastomes of each species formed reciprocally monophyletic groups.  Plastomes were constructed de novo from Illumina short reads, aligned using MAFFT, and a partitioned maximum likelihood analysis was performed in IQTree. Among the dwarf milkweed species, A. eastwoodiana and A. uncialis were reciprocally monophyletic. Asclepias ruthiae and A. sanjuanensis, whose ranges are closest geographically, were not reciprocally monophyletic due to the nesting of a single A. sanjuanensis individual among the A. ruthiae samples. However, each grouping of individuals was well supported and the overall results largely support continued recognition of four rather than one species, which is in agreement with recent results based on population genetic analyses.

1 - Hobart and William Smith Colleges, Department of Biology, 300 Pulteney St., Geneva, NY, 14456, USA
2 - 1038 West C St., Apt. B, Moscow, ID, 83843, United States
3 - Oklahoma State University, Department of Plant Biology, Ecology, and Evolution, 301 Physical Sciences, Stillwater, OK, 74078, USA

Keywords:
Asclepias
Apocynaceae
reciprocal monophyly
plastome
phylogeny.

Presentation Type: Recent Topics Poster
Session: P, Recent Topics Posters
Location: Grand Ballroom - Exhibit Hall/Mayo Civic Center
Date: Monday, July 23rd, 2018
Time: 5:30 PM
Number: PRT028
Abstract ID:1324
Candidate for Awards:None