Systematics Section / ASPT
Grose, Susan O. , Olmstead, Richard .
The role of morphology in placing unsampled taxa in molecular phylogenies: A case study using Bignoniaceae.
One of the many problems facing systematists today is the placement of unsampled taxa into a molecular phylogeny. In many cases, these taxa are not sampled due to extinction, limitations on field work, or are available only as fossils from which DNA cannot be obtained. Morphology has been established as problematical for use in phylogeny reconstruction based on difficulties in character conceptualization, homology assessment and small numbers of unambiguous characters. However, morphology does have a place in phylogenetic studies, especially when there is an objective context in which it can be analyzed. Here, a study is presented in which tests are done to determine the ability of morphology to accurately predict a placement of a particular taxon in a molecular phylogeny. In two well sampled genera of Bignoniaceae, Amphitecna and Parmentiera, several randomly chosen species were left out of the molecular phylogeny. Predictions as to their placement were then made based on their morphology or published description. To test the predicted placement, the sequences from these species were obtained, added to the alignment and used to produce a new tree. Based on the results of this study, the position of several extinct or otherwise unsamplable species within the Tabebuieae can be placed with measurable confidence within the phylogeny.
1 - University of Washington, Biology, Seattle, Washington, 98195-5325
Presentation Type: Paper
Location: Cottonwood A (Snowbird Center)
Date: Tuesday, August 3rd, 2004
Time: 8:45 AM