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Abstract Detail

Genomics / Proteomics

Lin, Qianshi [1], Marques, Isabel [2], Macfarlane, Terry D.  [3], Conran, John G. [4], Graham, Sean W. [1].

Using a duplicated nuclear gene (phosphoglycerate kinase; PGK) to explore the phylogeny of the aquatic plant family Hydatellaceae.

Hydatellaceae are a small aquatic family of 12 species related to water lilies, part of the ANITA grade of angiosperms. Our current understanding of the family’s phylogenetic relationships comes from several plastid genes and nuclear ITS data. These data sets are generally highly congruent, and lend support to the monophyly of multiple species. However, the published nuclear ITS tree was unrooted (outgroups were too distant to align), and there were several minor phylogenetic conflicts between plastid and ITS gene trees for three closely related species, Trithuria bibracteata, T. occidentalis, and T. submersa; two of these species were not also not reciprocally monophyletic in individual gene trees. A species tree for the family derived using a multi-species coalescent analysis was generally well supported, with several minor exceptions. To further clarify phylogenetic relationships in the family and address species boundaries in the T. submersa species complex, we recovered the nuclear-encoded phosphoglycerate kinase (PGK) gene from Hydatellaceae and several water lilies, which we used as an additional phylogenetic marker in the family. We also added plastid and ITS data from additional populations of several species. The PGK gene tree is consistent with there having been an ancient duplication that pre-dated the origin of the water-lily order Nymphaeales, and perhaps angiosperms. Relationships within each putative gene copy are consistent with the overall relationships inferred using plastid and ITS data, but with less sharply defined species boundaries, consistent with local incomplete lineage sorting. We estimated the species tree using a bayesian multispecies coalescent approach for all available data (treating the two PGK copies as independent loci); this approach assumes that incongruence between genes is due to incomplete lineage sorting. Our analysis examined relationships within the submersa/bibracteata complex, and provided improved support for other relationships, including nuclear evidence for a root of the family between tropical and temperate clades, which is also observed using plastid data. We also address the possibility here that some of the incongruence that we observed is a consequence of additional minor gene duplications or allopolyploidization/introgression.

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1 - University of British Columbia, Botany, 3529 - 6270 University Boulevard, Vancouver, BC, V6T 1Z4, Canada
2 - University Of British Columbia, Dept of Botany, 3529-6270 University Blvd, Vancouver, BC, V6T1Z4, Canada
3 - Western Australian Herbarium, Department of Parks and Wildlife, Brain Street, Manjimup, WA, 6258, Australia
4 - The University Of Adelaide, ACEBB EEB/EES, Benham Bldg, DX650 312, Adelaide, N/A, SA 5005, Australia

ANITA grade
gene tree
gene duplication
species tree
low-copy nuclear genes
multi-species coalescent
water lilies.

Presentation Type: Oral Paper:Papers for Topics
Session: 35
Location: Pines South/Boise Centre
Date: Wednesday, July 30th, 2014
Time: 8:30 AM
Number: 35003
Abstract ID:787
Candidate for Awards:None

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