Abstract Detail

Phylogenomics

Loke, Elena [1], McDonnell, Angela [4], Moore, Michael [2], Sakai, Ann [3], Skogen, Krissa [4], Wagner, Warren [5], Weller, Stephen [3], Weisenberger, Lauren [6], Wickett, Norman [4].

Incorporating Phased Alleles to Reconstruct a Recent and Rapid Radiation in Schiedea (Caryophyllaceae).

Schiedea (Carophyllaceae), a monophyletic genus of 34 species endemic to the Hawaiian Islands, is a prime example of a recent, rapid adaptive radiation. Within the native flora, the genus is the fifth largest and has the greatest intrageneric diversity of breeding systems. Schiedea section Schiedea comprises 12 species that together exhibit the greatest diversity of breeding systems within the genus, ranging from hermaphroditic selfing to dioecious outcrossing (dioecy, subdioecy, and gynodioecy). However, the number of transitions to dioecy is unknown, due primarily to the lack of phylogenetic resolution among the 12 species. In rapid radiations, ancestral allele pools may not sort into descendant lineages in a way that is consistent with the process of speciation. This process, known as deep coalescence, leads to conflict between the gene tree and the “true” species tree (Incomplete Lineage Sorting), which makes inferring phylogenetic trees difficult. Densely sampling the allele pools of multiple species or individuals may improve phylogenetic resolution and accuracy. I generated a de novo dataset for Schiedea using next-generation sequencing and assembled four sub-datasets from the sequencing reads by following a recently published protocol (Kates et al. 2018) of new phylogenetic analytical methods that consider allelic variation. My study included the most thorough sampling of Schiedea section Schiedea to date: I sampled two to five individuals per species to capture the diversity among and between individuals, populations, and islands. Similar topologies for section Schiedea were inferred with minor differences between the four datasets, and inclusion of alleles slightly increased support and resolution compared to selecting a single consensus allele. All species of section Schiedea are heavily influenced by incomplete lineage sorting, but the greatest amount of deep coalescence was recovered for species that diverged more recently. Biogeography greatly influenced different modes of speciation within and between islands, but accurate estimations for the number of transitions for habit, pollination mode, and breeding system within section Schiedea were hindered by lack of sampling from all 34 species of Schiedea. Extensive hybridization was inferred in the following recently diverging species: S. adamantis, S. hookeri, S. kealiae, S. ligustrina, S. lydgatei, S. mannii, S. menziesii, S. salicaria, and S. sarmentosa. Despite dominant patterns of incomplete lineage sorting, hybridization, and low gene tree resolution, species of section Schiedea were recovered in five clades consistently between datasets, suggesting that there is strong evidence of evolutionary cohesion between the species.

1 - 164 Ivy Drive, Orinda, CA, 94563, United States
2 - Oberlin College, Department Of Biology, 119 Woodland St., Science Center K111, Oberlin, OH, 44074, United States
3 - Univ. California-Irvine, Department of Ecology and Evolutionary Biology, Irvine, CA, 92697, USA
4 - Chicago Botanic Garden, 1000 Lake Cook Rd., Glencoe, IL, 60022, United States
5 - Smithsonian Institution, Department Of Botany, MRC-166, P. O. Box 37012, Washington, DC, 20013, United States
6 - US Fish and Wildlife Service, Pacific Islands Fish and Wildlife Office, 300 Ala Moana Boulevard, Room 3-122, Honolulu, HI, 96850, USA

Keywords:
Schiedea
Hawaiian Islands
HybSeq
Target Enrichment
Alleles
Incomplete Lineage Sorting
Carophyllaceae
Radiation.

Presentation Type: Oral Paper
Number: PHYLO III016
Abstract ID:279
Candidate for Awards:None