School Seminars and Colloquia

Spectral Envelope and Phylogenetic Trees

BELZ Lecture Series

by Professor Chris Field

Institution: Dalhousie University, Canada
Date: Thu 15th February 2007
Time: 4:00 PM
Location: Old Geology Theatre 2, The University of Melbourne

Abstract: The objective is to determine the phylogenetic tree or relationship among a set of T species (taxa) based on their amino acid sequence of n characters (20 different amino acids). The usual Markov models for evolution assume that evolution occurs independently at each site. Molecular Evolutionists know that is not true but it becomes difficult to incorporate dependence into the usual ML models. As an
alternative approach, we use the spectral envelope method which was developed in Stoffer et al. (2000) as a general framework for frequency domain analysis of categorical time series by scaling of categorical time series. The spectral envelope of an amino acid sequence gives a characterization of a gene and we use a spectral covariance as a distance measure for building a phylogenetic tree. We illustrate the procedure using myoglobin sequences for primates and cetaceans.

For More Information: Dr Owen Jones: