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Systematics Section / ASPT

Keeley, Sterling C. [1], Forsman, Zac H. [2], Chan, R. [3].

Phylogenetic Signal and Congruence in Nuclear and Chloroplast DNA Data in the Vernonieae (Asteraceae).

We examined 93 taxa within the tribe Vernonieae using two chloroplast regions, the coding ndhF and the non-coding intergenic spacer region trnLc-f, and the nuclear rDNA ITS region. The data sets were examined separately and in combination after tests revealed congruence and homogeneity among data sets. A comparison of alternative multiple alignments of the ITS region revealed strong phylogenetic signal and a robust topology that was insensitive to alignment perturbations. The three gene regions yielded congruent topologies using MP, NJ and ML analyses, resolving the same terminal clades with strong statistical support. The separate analyses showed weak bootstrap support and lack of resolution at deeper branches. When the data sets were combined, however, greater resolution and stronger support were obtained for midrange and deep nodes in the tree. The combined data analyses showed clearly monophyletic Old World and New World groups, resolving previously conflicting results. There was a strongly supported basal clade composed of taxa from east Africa and Madagascar. Notable among these basal taxa was the Hawaiian endemic Hesperomannia. There are clear biogeographic patterns within New and Old World clades that provide information on the timing, radiations and origins of the geographical subgroups within the tribe.


1 - University of Hawaii, Botany, 3190 Maile Way, #101, Honolulu, Hawaii, 96822-2279, United States
2 - Univeristy of Hawaii, Biology Program, Dean Hall, Honolulu, Hawaii, 96822-2279, United States
3 - University of Hawaii, Department of Botany, Manoa, Oahu, Hawaii, 96822-2279, USA

Keywords:
ITS sequence
adaptive radiation
biogeography
chloroplast DNA
cladistic analysis
Compositae
computationally intensive analyses
cpDNA
divergence time estimates
geographical distribution
Hawaii
island biogeography
long-distance dispersal
molecular phylogenetics
molecular systematics
ndhF
nrDNA ITS sequences
nucleotide characters
Pacific
partitioned models
PAUP*
phylogenetic systematics
phylogeny reconstruction
plant systematics
radiation
sunflower
trnL-F
Vernonieae
Asteraceae
congruence.

Presentation Type: Paper
Session: 3-8
Location: Cottonwood B (Snowbird Center)
Date: Monday, August 2nd, 2004
Time: 9:45 AM
Abstract ID:538


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