Error, Bias, and Long-Branch Attraction in Data for Two Chloroplast Photosystem Genes in Seed Plants


Autoria(s): Sanderson, M.J.; Wojciechowski, M.F.; Hu, J.M.; Sher Khan, T.; Brady, S.G.
Data(s)

2000

Resumo

Sequences of two chloroplast photosystem genes, psaA and psbB, together comprising about 3,500 bp, were obtained for all five major groups of extant seed plants and several outgroups among other vascular plants. Strongly supported, but significantly conflicting, phylogenetic signals were obtained in parsimony analyses from partitions of the data into first and second codon positions versus third positions. In the former, both genes agreed on a monophyletic gymnosperms, with Gnetales closely related to certain conifers. In the latter, Gnetales are inferred to be the sister group of all other seed plants, with gymnosperms paraphyletic. None of the data supported the modern ‘‘anthophyte hypothesis,’’ which places Gnetales as the sister group of flowering plants. A series of simulation studies were undertaken to examine the error rate for parsimony inference. Three kinds of errors were examined: random error, systematic bias (both properties of finite data sets), and statistical inconsistency owing to long-branch attraction (an asymptotic property). Parsimony reconstructions were extremely biased for third-position data for psbB. Regardless of the true underlying tree, a tree in which Gnetales are sister to all other seed plants was likely to be reconstructed for these data. None of the combinations of genes or partitions permits the anthophyte tree to be reconstructed with high probability. Simulations of progressively larger data sets indicate the existence of long-branch attraction (statistical inconsistency) for third-position psbB data if either the anthophyte tree or the gymnosperm tree is correct. This is also true for the anthophyte tree using either psaA third positions or psbB first and second positions. A factor contributing to bias and inconsistency is extremely short branches at the base of the seed plant radiation, coupled with extremely high rates in Gnetales and nonseed plant outgroups. M. J. Sanderson,* M. F. Wojciechowski,*† J.-M. Hu,* T. Sher Khan,* and S. G. Brady

Formato

application/pdf

Identificador

http://eprints.qut.edu.au/26171/

Publicador

Oxford University Press Inc

Relação

http://eprints.qut.edu.au/26171/1/26171.pdf

http://mbe.oxfordjournals.org/cgi/reprint/17/5/782

Sanderson, M.J., Wojciechowski, M.F., Hu, J.M., Sher Khan, T., & Brady, S.G. (2000) Error, Bias, and Long-Branch Attraction in Data for Two Chloroplast Photosystem Genes in Seed Plants. Molecular Biology and Evolution, 17(5), pp. 782-797.

Direitos

Society for Molecular Biology and Evolution

Fonte

Biogeoscience; Faculty of Science and Technology

Palavras-Chave #060300 EVOLUTIONARY BIOLOGY #statistical consistency #maximum likelihood #parsimony.
Tipo

Journal Article