Iles, Will , Smith, Selena Y. , Graham, Sean W. .
Robust resolution of the backbone of Alismatales phylogeny.
The order Alismatales represents one of the earliest splits in monocot phylogeny. Alismatales is divided into three major subclades: the aroids, Araceae (~4000 species), Tofieldiaceae (~30 species) and a core alismatid group comprising ~12 families (~400 species). Relationships between these three clades and among the ~14 core alismatid families often lack strong support in phylogenetic analyses. To improve our knowledge of these relationships we collected a subset of the plastid genome (~14 kb per taxon) from 30 representative taxa in the order, surveying one or more exemplars per family. Our phylogenetic analyses (parsimony and likelihood) resolve interfamilial relationships that were often poorly supported, but here with strong support. We confirm recent suggestions that the eastern Australian endemic Maundia (Juncaginaceae) is the sister group of a clade containing 4-5 families, supporting its recognition as a family. We also recover the monogeneric Ruppiaceae as nested within Cymodoceaceae, supporting its inclusion in that family. We uncovered intriguing molecular evolutionary phenomena in the surveyed genes. For example, there appear to have been parallel losses of ndh genes in the order. In addition, one or more regions in the plastid inverted repeat region exhibit considerable heterotachous rate variation. We re-evaluate the ages of the crown group of Alismatales and of the origin of the lineages that returned to marine habitats (the sea grasses).
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1 - University of British Columbia, Botanical Garden And Centre For Plant Research, 6804 Sw Marine Drive, Vancouver, BC, V6T 1Z4, Canada
2 - University of Michigan, Dept. of Geological Sciences, 2534 CC Little Bldg, 1100 North University Ave, Ann Arbor, MI, 48109, USA
3 - University of British Columbia, Botanical Garden And Centre For Plant Research, 6804 Sw Marine Drive, Vancouver, British Columbia, V6T 1Z4, Canada
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Cottonwood A/Snowbird Center
Date: Monday, July 27th, 2009
Time: 1:15 PM