Abstract Detail

Systematics Section/ASPT

McDaniel, James [1], Cameron, Kenneth M. [1].

Phylogenetic Utility of Genotyping by Sequencing (GBS) at the Species-Level: An Example from Flowering Plants (Porroglossum: Orchidaceae).

The Neotropical orchid genus Porroglossum, nested within the subtribe Pleurothallidinae, is composed of 52 described species that are distributed throughout South America from Venezuela south to Colombia, Ecuador, Peru, and Bolivia. The flowers of Porroglossum set it apart from nearly all other ‘pleurothallids’ because physical stimulation of the labellum causes it to actively snap inward thereby thrusting pollinators against the column to ensure pollination. Within the Pleurothallidinae, motility of the labellum has only evolved in four lineages and Porroglossum is truly unique because it contains a disproportionate number of species when compared to the other three lineages. Recently, we reconstructed the evolutionary history of Porroglossum using a combination of nuclear (XDH), ribosomal (nrITS), and plastid (matK, ycf1, rpl32-trnL) markers. Four clades, which partially support previous taxonomic circumscriptions of the genus, were recovered with strong support: Echidnae (99% bs), Brevisepala (95% bs), Porroglossum (95% bs), and Tortae (99% bs); however, the backbone of the phylogeny and interspecific relationships remained unresolved. Additionally, a majority of the species were characterized by relatively short branch lengths indicating the possibility of a recent origin for the genus. As a result, this study explores the utility of reduced-representation genome sequencing in the form of genotyping by sequencing (GBS) for phylogenetic inference at the species-level. Genomic DNA samples for 25 species of Porroglossum and one outgroup were digested using the restriction enzyme ApeKI and sequenced on a HiSeq2000 generating single-end, 100 bp reads. By utilizing high-throughput computing, we implemented the Stacks pipeline to generate thousands of SNPs from the raw sequence data for phylogenetic inference. Support values for the clades recovered using traditional Sanger sequencing were bolstered (100% bs). Furthermore, the backbone of the phylogeny along with interspecific relationships became resolved with strong support. Results will be discussed as well as the various parameters that we utilized in Stacks, which produced largely congruent topologies with varying numbers of loci/SNPs.

1 - University of Wisconsin - Madison, Botany, 430 Lincoln Drive, Madison, WI, 53706, USA

Keywords:
Orchidaceae
Pleurothallidinae
GBS
Phylogenetics
stacks
loci
SNPs.

Presentation Type: Oral Paper:Papers for Sections
Session: 31
Location: Salon 4/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 8:30 AM
Number: 31003
Abstract ID:925
Candidate for Awards:George R. Cooley Award