Systematics/Phytogeography / Taxonomie/ Section
Moore, Michael , Bell, Charles , Soltis, Pamela S. , Soltis, Douglas E. .
Analysis of an 83-gene, 86-taxon plastid genome data set resolves relationships among several recalcitrant deep-level eudicot lineages.
Over the past few years, the burgeoning field of plastid genomics has enabled systematists to use data sets of > 40,000 aligned bases to resolve several difficult deep-level nodes in the Angiosperm Tree of Life. For example, plastid genome-scale data sets have provided strong support for the successive sister relationships of Amborella, Nymphaeales, and Austrobaileyales to all other angiosperms, as well as for a clade of monocots + (Ceratophyllum + eudicots). Despite this progress, other deeper-level problem areas remain in angiosperm phylogeny, including the relationships among basal eudicot lineages, basal core eudicot lineages, and many basal lineages of rosids and asterids. As part of the Angiosperm Tree of Life project, we sequenced 27 eudicot plastid genomes, selected to cover all major basal eudicot and core eudicot lineages, in an effort to resolve recalcitrant nodes. By combining these new genomes with existing genomes, we created an 86-taxon, 66,741 bp alignment, including all 79 angiosperm plastid protein-coding genes and 4 rRNA genes. Maximum likelihood (ML)-based analyses of these data provided strong (> 90% ML bootstrap) or moderate (70-90% ML bootstrap) support for a resolution of several previously difficult-to-resolve eudicot nodes. Notable examples include (1) moderate support for a sister relationship between Sabiaceae and Proteales, (2) moderate support for a sister relationship of Dilleniaceae to a clade of Vitaceae, Saxifragales, and rosids, (3) moderate support for a sister relationship of Caryophyllales to asterids, and (4) strong support for the successive sister relationships of Santalales and Berberidopsidales to Caryophyllales + asterids. However, even with plastid genome-scale data, our analyses do not allow for confident topological resolution (ML bootstrap < 70%) among the following eudicot lineages: (1) Buxales, Trochodendrales, and core eudicots, (2) Vitaceae, Saxifragales, and rosids, and (3) the four lineages of basal lamiids included in our analyses (Boraginales, Lamiales, Solanales, and Gentianales).
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1 - Oberlin College, Biology Department, 119 Woodland Street, Science Center K111, Oberlin, Ohio, 44074-1097, USA
2 - University of New Orleans, Department of Biological Sciences, New Orleans, LA, 70148, USA
3 - University of Florida, Florida Museum of Natural History, PO Box 117800, Gainesville, FL, 32611-7800, USA
4 - University of Florida, Department of Botany, 220 Bartram Hall, P.O. Box 118526, Gainesville, Florida, 32611-8526, USA
basal core eudicots
Angiosperm Tree of Life.
Presentation Type: Oral Paper:Papers for Sections
Location: Room 6/Woodward
Date: Tuesday, July 29th, 2008
Time: 10:30 AM