Abstract Detail

Methods and theory of phylogenetic inference

Graham, Sean W. [1].

(Mis)rooting phylogenetic trees.

The production of poorly rooted phylogenetic trees is a major stumbling block for correctly assembling and using the Tree of Life, because the root of an ingroup tree provides the "arrow of time" for inferences made about (and from) ingroup phylogeny. Even a small misdirection in root placement can have profound consequences for inferences of taxon monophyly in the ingroup, or for reconstructions of character evolution. In the outgroup method (the most widely used approach for rooting trees), the root node of an ingroup tree is simply the point connecting it with its nearest relatives. Unfortunately, the root node can be misplaced when, for example, the branch connecting the ingroup to the nearest outgroup node is long enough that systematic error misleads phylogenetic inference. Here I use various examples from seed-plant phylogeny to demonstrate the potential for tree misrooting under a variety of circumstances, and discuss the utility of various approaches for detecting misrooting and correcting it.

Related Links:
Institutional website

1 - University of British Columbia, UBC Botanical Garden and Centre for Plant Research, 6804 SW Marine Drive, Vancouver, British Columbia, V6T 1Z4, Canada

Keywords:
trees
phylogenetic inference
systematic error
long-branch attraction
rooting
Tree of Life
outgroup
ingroup
root node.

Presentation Type: Symposium
Session: 39-1
Location: Alpine A (Snowbird Center)
Date: Tuesday, August 3rd, 2004
Time: 2:30 PM
Abstract ID:56