Abstract Detail

Revolutionizing systematics: Herbaria in the Genomics Age

Acha Macias , Serena I [1], Edwards, Christine [2], MacDougal, John [3].

Phylogenomics of Passiflora sect. Decaloba reveals strong biographic structuring of clades.

Because of their extraordinary flower morphology and highly variable leaf shape, Passion flowers (Passifloraceae) have been of interest to naturalists since their discovery. The genus Passiflora is the largest in the family, and with 600 species grouped in subgenera, super sections and sections, it represents a major challenge to scientists interested in understanding their evolutionary history and relationships. One of the most enigmatic and species-rich (130 spp.) groups in Passiflora is section Decaloba, which occurs in the Neotropics and is particularly diverse in Andean montaine forests. A recent study of the phylogeny of Passifloraceae recovered the monophyly of section Decaloba; however, despite the use of multiple DNA regions, the evolutionary relationships and biogeography of species within the clade remained unresolved. The goal of this study was to elucidate the phylogeny and biogeography of Section Decaloba. We sampled leaf tissue from herbarium specimens collected between 1943-2013 in the Missouri Botanical Garden herbarium, including several accessions of most species, and recovered high-quality DNA from samples collected as long ago as 1974. We used a high-throughput DNA sequencing technique called 2b-RAD-seq to sequence a large number of DNA characters from throughout the genome of each accession and processed the resulting data using ipyrad. Although the success rate using herbarium samples was significantly lower than is typically found for silica-dried material, we were able to produce a data set containing nearly 600,000 characters from >100 accessions. Based on this data set, we reconstructed the phylogeny using parsimony and Bayesian approaches and recovered a predominantly well-supported and well-resolved tree in which relationships strongly corresponded to geography. One clade contained taxa from central America, one contained taxa from lowland South America, and one contained Andean species, which was further divided into two geographically structured clades containing taxa from Northern Ecuador/Northern Andes or southern Ecuador/southern Andes. Relationships recovered in the 2b-RAD-seq phylogeny were also supported by morphological features, such as the length-to-width ratios of leaves. To our knowledge, this study is one of only a few to reconstruct a phylogeny of a large clade using only herbarium samples and a RAD-seq approach. This study shows that that it is possible to use herbarium material and next-generation DNA sequencing approaches to elucidate the phylogenetic relationships of groups for which field collections are unfeasible.

1 - University of Missouri St. Louis, Biology, One University Blvd, St. Louis, MO, 63121, USA
2 - Missouri Botanical Garden, Center for Conservation and Sustainable Development, Missouri Botanical Garden , 4344 Shaw Blvd., St. Louis, MO, 63110, USA
3 - Harris–Stowe State University, Department of Mathematics and Natural Sciences, 3026 Laclede Ave., St. Louis, MO, 63103 , USA

Keywords:
2b-RAD
vines
passion flower
Neotropics
Andes.

Presentation Type: Colloquium Presentations
Session: C10, Revolutionizing Systematics: Herbaria in the Genomics Age
Location: 103/Mayo Civic Center
Date: Wednesday, July 25th, 2018
Time: 9:00 AM
Number: C10005
Abstract ID:623
Candidate for Awards:None