Inferring angiosperm phylogeny from EST data with widespread gene duplication.
BACKGROUND
Most studies inferring species phylogenies use sequences from single copy genes or sets of orthologs culled from gene families. For taxa such as plants, with very high levels of gene duplication in their nuclear genomes, this has limited the exploitation of nuclear sequences for phylogenetic studies, such as those available in large EST libraries. One rarely used method of inference, gene tree parsimony, can infer species trees from gene families undergoing duplication and loss, but its performance has not been evaluated at a phylogenomic scale for EST data in plants.


RESULTS
A gene tree parsimony analysis based on EST data was undertaken for six angiosperm model species and Pinus, an outgroup. Although a large fraction of the tentative consensus sequences obtained from the TIGR database of ESTs was assembled into homologous clusters too small to be phylogenetically informative, some 557 clusters contained promising levels of information. Based on maximum likelihood estimates of the gene trees obtained from these clusters, gene tree parsimony correctly inferred the accepted species tree with strong statistical support. A slight variant of this species tree was obtained when maximum parsimony was used to infer the individual gene trees instead.


CONCLUSIONS
Despite the complexity of the EST data and the relatively small fraction eventually used in inferring a species tree, the gene tree parsimony method performed well in the face of very high apparent rates of duplication.
Sanderson
Michael J
MJ
Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA. sanderm@email.arizona.edu
McMahon
Michelle M
MM
D000465:Algorithms; D019143:Evolution, Molecular; D020224:Expressed Sequence Tags; D020440:Gene Duplication; D019684:Magnoliopsida / Q000235:genetics*; D008957:Models, Genetic; D010802:Phylogeny; D017422:Sequence Analysis, DNA / Q000379:methods