Abstract Detail

Systematics

Garcia, Nicolas [1], Meerow, Alan W. [2], Chamala, Srikar [3], Gitzendanner, Matthew [1], Oliveira, Renata S. [4], Folk, Ryan [1], Soltis, Douglas [1], Soltis, Pamela  S. [1].

Revisiting incongruence in the diploid phylogeny of Amaryllidaceae tribe Hippeastreae (Asparagales): hybridization or incomplete lineage sorting?

Amaryllidaceae tribe Hippeastreae constitute a horticulturally valuable group of approximately 180 species of American petaloid monocots, characterized by dysploidy and polyploidy. A recent hypothesis based on ITS and chloroplast sequence data states that Hippeastreae experienced ancient diploid hybridization(s) that preceded the radiation of the major subclade, Hippeastrinae. Target-enriched DNA libraries were sequenced on the Illumina MiSeq platform for 35 ingroup taxa (representing only diploid taxa) plus five outgroups. Gene trees and coalescent-based species trees were estimated using 18 nuclear loci. Species tree and concordance analyses suggest two major clades within Hippeastrinae, one characterized by 2n = 22 (Tocantinia, Hippeastrum) and another by 2n = 12, 14, and 18 (Eithea, Habranthus, Rhodophiala, Zephyranthes). Whole chloroplast genome (cpDNA) sequences were extracted from Illumina reads, and we analyzed an edited alignment of ca. 130,000 bp (after removing one inverted repeat and problematic regions) with 2% missing data. A strongly supported cpDNA tree was obtained, albeit strongly conflicting with the nuclear species tree regarding relationships in Hippeastrinae. Network analyses were performed to summarize conflicts among nuclear loci and between nuclear and cpDNA data. The source of incongruence was explored with JML (posterior predictive approach) and coalescent simulations. The resulting phylogenetic framework will serve as a basis for understanding patterns of character evolution in Hippeastreae and for reclassification of the tribe at the generic level.

1 - University Of Florida, Florida Museum Of Natural History, 1659 Museum Rd., Gainesville, FL, 32611, USA
2 - USDA-ARS-SHRS, UNITED STATES DEPARTMENT OF AGRICULTURE, 13601 Old Cutler Road, Miami, FL, 33158, USA
3 - University of Florida, Department of Pathology, Gainesville, FL, 32610, USA
4 - Universidade de Sao Paulo, Departamento de Botanica, Instituto de Biociencias, Rua do Matao 277, Sao Paulo, SP, Brazil

Keywords:
monocots
target-enrichment
cytonuclear discordance
phylogenomics
networks.

Presentation Type: Oral Paper
Session: 20, Basal Dicots/Monocots part A (Asparagales)
Location: 200/Savannah International Trade and Convention Center
Date: Tuesday, August 2nd, 2016
Time: 10:15 AM
Number: 20009
Abstract ID:437
Candidate for Awards:None