Abstract Detail

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

Rai, Hardeep [1], Parks, Matthew [2], Holman, Garth [3], Dittmar, Emily [1], Frank, Margaret [4], Tyagi, Sameer [1], Liu, Cindy [1], Kim, Eunsuk [1], Jin, Sharon [1], Wu, Yihao [1], Chonofsky, Mark [1], Mathews, Genny [1], Nagalingum, Nathalie [5], Mathews, Sarah [1].

Phytochrome data: a little goes a long way in acrogymnosperm phylogenetics.

As part of the collaborative Gymnosperms on the Tree of Life project, we will present results from phylogenetic analyses of two independently evolving nuclear loci (PHYN and PHYP), sampled from ~160 extant gymnosperm species (~16 of the total extant diversity) covering all critical nodes in available trees. When aligned and concatenated, our matrix comprises 7013 nucleotide sites representing parts of exons I and II and the intervening intron (unaligned the two fragments together average ~3561 sites). This relatively small number of characters provides a surprisingly large amount of information. Our preliminary analyses are largely congruent with, and have comparable (in some cases, better) maximum likelihood (ML) bootstrap support to, several recent multi-gene studies focused on resolving relationships within Coniferae and their placement within seed plants. This two-gene data set recovers ~75% of all nodes within gymnosperms with greater than 90% ML bootstrap support. As other nucleotide data have done, the combined PHY data support the sister group relationship of Pinaceae and Gnetophyta. However, the level of support for this relationship is not as high as that noted in some published trees. For this reason, and because whole plastome data suggest that Gnetophyta are sister to Cupressophyta rather than Pinaceae, we used a duplicate gene rooting approach to evaluate the relationships among Pinaceae, Gnetophyta and Cupressophyta. Since the resulting gene tree can be rooted on the branch that joins the PHYN and PHYP clades, sequences from other seed plants, all of which are rather divergent from the conifer clades and Gnetophyta, can be excluded from the analysis. Our preliminary analyses using this approach suggest that conifers are monophyletic.

Broader Impacts:

1 - Harvard University, Arnold Arboretum, Harvard University Herbaria, 22 Divinity Avenue, Cambridge, MA, 02138, USA
2 - Oregon State University, Department of Botany and Plant Pathology, 2082 Cordley Hall, Corvallis, OR, 97331, USA
3 - University of Maine, School of Biology and Ecology, Orono, ME, 04469-5735, USA
4 - Cornell University, Department of Plant Biology, Ithaca, New York, 14853, (USA)
5 - University of California - Berkeley, Department of Integrative Biology, 3060 Valley Life Sciences Building, Berkeley, CA, 94720-3140, USA

Keywords:
gnepine
gnecup
gnetales
phytochrome
phylogeny
systematics.

Presentation Type: Symposium or Colloquium Presentation
Session: C2
Location: Ballroom C/Convention Center
Date: Monday, August 2nd, 2010
Time: 3:45 PM
Number: C2011
Abstract ID:756