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Testing for differences in rates-across-sites distributions in phylogenetic subtrees
Edward Susko1, Yuji Inagaki, Chris Field
1Department of Mathematics and Statistics, Dalhousie University, Halifax, Nova Scotia, Canada. susko@mathstat.dal.ca
Molecular Biology and Evolution
|August 30, 2002
Summary
Evolutionary rates at protein sites can change across different evolutionary subtrees. This study introduces methods to detect and pinpoint these rate shifts, improving phylogenetic inference.
Area of Science:
- Evolutionary Biology
- Molecular Evolution
- Phylogenetics
Background:
- Protein molecular evolution rates vary across sites.
- Traditional models assume fixed rates per site throughout evolutionary history.
- Recent findings suggest rates can also vary across subtrees.
Purpose of the Study:
- To develop methods for detecting rate variation across subtrees.
- To identify specific locations of rate changes within phylogenetic trees.
- To enhance phylogenetic inference by accounting for dynamic evolutionary rates.
Main Methods:
- Parametric bootstrapping for testing rate differences.
- Orthogonal regression for analyzing rate variation.
- Confidence intervals based on conditional site rate distributions.
Main Results:
- Methods successfully detect rate heterogeneity across subtrees.
- Specific sites exhibiting rate changes are identified.
- Quantifiable differences in evolutionary rates between subtrees are established.
Conclusions:
- Site-specific evolutionary rates are not always fixed.
- The covarion model better captures observed rate dynamics.
- Accurate detection of rate variation is crucial for deep phylogenetic inference.