Abstract Detail



Systematics

acha, serena [1], Edwards, Christine [1], MacDougal, John [3].

A history of Vines in the Andes, is Passiflora alnifolia one or 15 species?

The genus Passiflora is a fascinating group of mostly tropical vines that encompasses a broad range of diversity in both floral and leaf morphological features. In the tropical Andes of Colombia and Ecuador, several Passiflora species, including P. alnifolia, P. chelidonea, P. tribolophylla and P. andreana, share highly similar morphology and distribution, have diffuse species limits, and are currently treated as a species complex.  Our goal was to determine patterns of genetic structure in the group, clarify how many lineages make up the “alnifolia complex,” and to understand how these lineages correspond to the taxonomy of the group. We sampled leaf tissue from 55 herbarium specimens corresponding to 14 taxonomic names at the Missouri Botanical Garden, including multiple accessions per species. 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. The resulting data was processed using Ipyrad and resulted in a data set of 231,600 characters, 1828 loci, 4779 variant sites and 1794 parsimony-informative sites.  We reconstructed the phylogeny using RAxML and Tetrad, analyzed genetic structure using STRUCTURE, Treemix and PCA, and analyzed these results in the context of both geography and morphology. We found that samples identified as P. alnifolia, P. chelidonea, P. tribolophylla and P. andreana  did not form monophyletic groups, such that the current delimitation of species in the alnifolia complex does not correspond to phylogenetic relationships or patterns of genetic structure. Results of STRUCTURE and phylogenetic analyses were concordant and identified four lineages: 1) one group found in higher elevations on the east side of the Ecuadorian Andes, ) one group found in higher elevations on the west side of the Ecuadorian Andes, 3) one lower elevation group found east of Ecuadorian Andes, and, 4) one clade that occurs on the northern limit of the distribution of the group, corresponding to, P. kalbreyeri. Our analyses also showed strong evidence of gene flow and hybridization among these lineages, especially in the Colombian Andes. Surprisingly, we also found areas where different lineages co-occured but no found gene flow among them. We propose a new delimitation for P. alnifolia, P. chelidonea, P. tribolophylla and P. andreana based on geography and genetic analysis; further analysis of morphology is necessary to identify whether individuals in this group share any characteristics that can be used to differentiate them.


1 -
2 - Missouri Botanical Garden, 4344 Shaw Blvd, 4344 Shaw Blvd, Saint Louis, MO, 63110, United States
3 - Harris-Stowe State University, Located at 3026 Laclede Ave., St. Louis, Missouri, 63103, United States

Keywords:
2b-RAD seq
Passiflora
Decaloba
Andes.

Presentation Type: Oral Paper
Number:
Abstract ID:713
Candidate for Awards:George R. Cooley Award


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