Abstract Detail

Symposia: Emerging Results from Studies of Gymnosperms on the Tree of Life II

Raubeson, Linda A. [1], Aguilera, Justina [2], Bunnell, Cristy [1], Campbell, Christopher S. [3], Chumley, Timothy W. [1], Cronn, RC [4], Dutton, Ashley [1], Gernandt, David S. [5], Holman, Garth [3], Kelch, Dean [6], Li, Jianhua [7], Liston, Aaron [8], Little, Damon [9], Mei, Wenbin [10], Morris, Julie A. [11], Parks, Matthew [12], Rai, Hardeep [13], Schwarzbach, Andrea E. [11], Smith, Daniel [10], Stevenson, Dennis Wm. [14], Talen, Josh [1], Mathews, Sarah [15].

Seed plant phylogeny – 78 plastid genes and 50 taxa – will more data make a difference?

As part of the Gymnosperm Tree of Life Project, we are generating plastome data from numerous gymnosperms. Following the approach of Cronn et al [2008, Nucleic Acids Research 36: e122], we are amplifying each plastome as a series of 3-4kb products and, upon pooling, using sequencing-by-synthesis (Solexa) to generate the sequence data. For this work, we will extract sequences for 78 plastid protein-coding genes and prepare an alignment that includes Ginkgo plus 4-6 members each of gnetales, cycads, Araucariaceae, Cupressaceae, Pinaceae, Podocarpacaeae, and Taxaceae, as well as representative angiosperms, and pteridophyte outgroups. Using this matrix, we will explore hypotheses of seed plant relationships. It has been challenging to determine these relationships and a number of hypotheses remain viable: gymnosperms may or may not be monophyletic; gnetales may be sister to all seed plants, sister to conifers (gnetifer hypothesis), sister to Pinaceae (gne-pine hypothesis), or sister to remaining conifers (gne-cup hypothesis); and Ginkgo and cycads may or may not be sister taxa. Initial work, using 61 plastid genes and minimal exemplars (one for each major lineage, 4 gymnosperms), the gne-cup hypothesis represented the optimal topology under parsimony or likelihood, however gnetifer and gne-pine hypotheses could not be statistically rejected. Upon increasing exemplars (13 gymnosperms) and plastid genes (83), even stronger support was seen for the gne-cup
scenario, but the gne-pine hypothesis still could not be rejected. The cycad-ginkgo relationship could not be determined with certainty using either of these smaller matrices, although gymnosperm monophyly received unambiguous support. The data set developed here will include significantly more gymnosperm taxa (35), and we will see if, with better sampling, support for the gne-cup hypothesis further strengthens, or if an alternative hypothesis then comes to the fore, and whether placement of the other lineages is clarified.

Broader Impacts:

Related Links:
Gymnosperm Tree of Life Project

1 - Central Washington University, Department of Biological Sciences, 400 E University Way, Ellensburg, WA, 98926-7537, USA
2 - Central Washington University, Department of Biological Sciences, Ellensburg, WA, 98926-7537
3 - University of Maine, School of Biology and Ecology, Orono, ME, 04469-5735, USA
4 - US Forest Service, Pacific NW Research Station, Genetics, 3200 SW Jefferson Way, Corvallis, Oregon, 97331, USA
5 - Instituto de Biología, Universidad Nacional Autonoma de Mexico, Departamento de Botánica, A. p. 70-367, Mexico, D.F., 04510, Mexico
6 - California Department of Food & Agriculture, 3294 Meadowview Road, Sacramento, California, 95832, USA
7 - Hope College, Biology, 35E 12th Street, Holland, MI, 49423, USA
8 - Oregon State University, Department of Botany & Plant Pathology, 2082 Cordley Hall, Corvallis, Oregon, 97331-2902, USA
9 - The New York Botanical Garden, Lewis B. and Dorothy Cullman Program for Molecular Systematic Studies, 200th St. & Southern Blvd., Bronx, New York, 10458-5126, USA
10 - Central Washington University, Department of Biological Sciences, 400 E University Way, Ellensburg, WA, 98926-7537
11 - The University of Texas-Brownsville, Department of Biological Sciences, 80 Fort Brown, Brownsville, TX, 78520, USA
12 - Oregon State University, Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, 97331, USA
13 - Harvard University, Arnold Arboretum, Harvard University Herbaria, 22 Divinity Avenue, Cambridge, MA, 02138, USA
14 - New York Botanical Garden, Institute of Systematic Botany, 200Th Street & Southern Boulevard, Bronx, New York, 10458-5126, USA
15 - Harvard University Arnold Arboretum, Cambridge, MA

Keywords:
seed plant phylogeny
plastome sequence.

Presentation Type: Symposium or Colloquium Presentation
Session: SY1
Location: Ballroom C/Convention Center
Date: Monday, August 2nd, 2010
Time: 10:30 AM
Number: SY1006
Abstract ID:277