Reconciling extreme branch length differences: decoupling time and rate through the evolutionary history of filmy ferns.

Journal Article

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.

Full Text

Duke Authors

Cited Authors

  • Schuettpelz, E; Pryer, KM

Published Date

  • June 2006

Published In

Volume / Issue

  • 55 / 3

Start / End Page

  • 485 - 502

PubMed ID

  • 16861211

International Standard Serial Number (ISSN)

  • 1063-5157

Digital Object Identifier (DOI)

  • 10.1080/10635150600755438

Language

  • eng

Conference Location

  • England