Skip Navigation

Systematic Biology 2006 55(3):485-502; doi:10.1080/10635150600755438
This Article
Right arrow Full Text Freely available
Right arrow FREE Full Text (PDF) Freely available
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrow Search for citing articles in:
ISI Web of Science (3)
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by Schuettpelz, E.
Right arrow Articles by Pryer, K. M.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Schuettpelz, E.
Right arrow Articles by Pryer, K. M.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© 2006 Society of Systematic Biologists

Reconciling Extreme Branch Length Differences: Decoupling Time and Rate through the Evolutionary History of Filmy Ferns

Eric Schuettpelz and Kathleen M. Pryer

Department of Biology, Duke University Durham, North Carolina, 27708, USA E-mail: ejs7{at}duke.edu; pryer{at}duke.edu

Edited by Thomas Buckley: Associate Editor


  Abstract

The rate of molecular evolution is not constant across the Tree of Life. Characterizing rate discrepancies and evaluating the relative roles of time and rate along branches through the past are both critical to a full understanding of evolutionary history. In this study, we explore the interactions of time and rate in filmy ferns (Hymenophyllaceae), a lineage with extreme branch length differences between the two major clades. We test for the presence of significant rate discrepancies within and between these clades, and we separate time and rate across the filmy fern phylogeny to simultaneously yield an evolutionary time scale of filmy fern diversification and reconstructions of ancestral rates of molecular evolution. Our results indicate that the branch length disparity observed between the major lineages of filmy ferns is indeed due to a significant difference in molecular evolutionary rate. The estimation of divergence times reveals that the timing of crown group diversification was not concurrent for the two lineages, and the reconstruction of ancestral rates of molecular evolution points to a substantial rate deceleration in one of the clades. Further analysis suggests that this may be due to a genome-wide deceleration in the rate of nucleotide substitution.

Keywords: Bayesian analysis; divergence time estimates; molecular clock; molecular rate heterogeneity; monilophyte phylogeny; penalized likelihood; rbcL

Received August 3, 2005; Revised November 15, 2005; Accepted March 13, 2006
Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.