[Popgenlunch] Seminar by Tracy Heath on using fossils in
phylogenetics, Wednesday August 29
joe at gs.washington.edu
Thu Aug 22 15:11:01 PDT 2013
Dr. Tracy Heath, a postdoc in John Huelsenbeck's lab at UC Berkeley, will be visiting on August 29, and has agreed to give an informal seminar on her current project:
Date: August 29
Where: The seminar will be in S110 Foege Building (the usual room for PopGenLunch)
Title: The Fossilized Birth-Death Process: A Coherent Model of Fossil Calibration for Divergence Time Estimation
(joint work by Tracy A. Heath, John P. Huelsenbeck, and Tanja Stadler)
Abstract: Accurate estimates of absolute node ages are critical for addressing a wide range of questions in evolutionary biology. Because molecular sequence data are not informative on absolute time, external data–most commonly fossil age estimates–are required to calibrate estimates of species divergence times. For Bayesian divergence-time methods, the common practice for calibration using fossil information involves placing arbitrarily-chosen and parameterized parametric distributions on internal nodes, often disregarding most of the information in the fossil record. The `fossilized birth-death' (FBD) process is a model for calibrating divergence-time estimates in a Bayesian framework, explicitly acknowledging that extant species and fossils are observations from the same macroevolutionary process. Under this model, absolute node age estimates are calibrated by a single diversification model and arbitrary calibration densities are not necessary. Moreover, the FBD model allows for inclusion of all available fossils. We performed analyses of simulated data and show that node-age estimation under the FBD model results in accurate estimates of species divergence times with realistic measures of statistical uncertainty, overcoming major limitations of standard divergence time estimation methods.
Tracy will be around after the seminar and is available to meet with people.
Joe Felsenstein joe at gs.washington.edu
Department of Genome Sciences and Department of Biology,
University of Washington, Box 355065, Seattle, WA 98195-5065 USA
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