Abstract Detail

Systematics

Cooper, Benjamin [1], Moore, Michael [2], Wickett, Norm [3], Overson, Rick [4], Johnson, Matthew [5], Skogen, Krissa [6].

Using target enrichment methods to resolve the phylogeny of Oenothera sect. Calylophus (Onagraceae) with 322 nuclear loci.

The Sundrops (Oenothera sect. Calylophus) are a group of 13 recognized taxa in the Evening Primrose family (Onagraceae) with a center of diversity in the south western United States and northern Mexico. Section Calylophus is an important study group because it offers an interesting opportunity to investigate functional trait evolution and reticulate speciation in plants. Within Calylophus, taxa fall into two clearly recognizable subsections. Between the subsections there appears to have been independent origins of gypsum endemism and two independent shifts in pollination from sphingophily (hawkmoth pollination) to melittophily (bee pollination) that were accompanied by transitions from vespertine to diurnal flowering. However, the current morphologically based circumscription of Calylophus is obscured by a pattern of overlapping variation suggestive of reticulate evolution. Section Calylophus is part of a larger radiation of Onagraceae endemic to the Madrean floristic region that likely underwent a rapid diversification during the Paleogene. Furthermore, the observed pattern of reticulate relationships suggest the basal radiation of the section was followed by glacial vicariance during the Quaternary period. As a result, prior phylogenetic attempts at reconstructing relationships among Calylophus using only a few loci revealed low haplotype diversity and little support for species relationships. Here, we use a target enrichment approach to produce the first well-supported molecular phylogeny of sect. Calylophus. This high-throughput approach has been shown to be particularly effective for phylogenetic applications at shallow evolutionary timescales. To provide a robust test for phylogenetic hypotheses in spite of possible reticulate species relationships, we sampled taxa across the geographic and morphological range of each of the 13 currently recognized taxa. Barcoded genomic DNA libraries were enriched for 322 highly conserved, low-copy nuclear loci using custom biotinylated baits. In order to maximize phylogenetic information within the section, we use HybPiper, a recently developed bioinformatics pipeline for targeted sequencing, to extract exons and flanking intron sequences from high-throughput sequencing reads. Multiple phylogenetic methods are used here to 1) Test the current phylogenetic hypothesis; 2) Revise the current taxonomy as needed, and; 3) Test hypotheses of reticulate evolution, glacial vicariance, pollinator shifts and independent origins of gypsum endemism. These data will provide an important resource for future studies investigating floral trait evolution and reticulate speciation in plants.

1 - Northwestern University/Chicago Botanic Garden, Plant Biology and Conservation, 1000 Lake Cook Rd, Plant Science, Glencoe, IL, 60022, USA
2 - Oberlin College, Biology, 119 Woodland St., Science Center K111, Oberlin, OH, 44074, USA
3 - Chicago Botanic Garden, Plant Science, 1000 Lake Cook Rd, Plant Science, Glancoe, IL, 60022, USA
4 - Chicago Botanic Garden, Plant Science, 1000 Lake Cook Rd, Plant Science, Glencoe, IL, 60022, USA
5 - Chicago Botanic Garden, Plant Sciences, 1000 Lake Cook Road, Glencoe, IL, 60626, United States
6 - Chicago Botanic Garden, Conservation Scientist, 1000 Lake Cook Road, Glencoe, IL, 60022, USA

Keywords:
target enrichment
coalescent
phylogenomics
onagraceae
floral evolution
reticulate evolution.

Presentation Type: Oral Paper
Session: 21, Cooley Awards I
Location: 201/Savannah International Trade and Convention Center
Date: Tuesday, August 2nd, 2016
Time: 9:00 AM
Number: 21005
Abstract ID:295
Candidate for Awards:George R. Cooley Award