Mathematical Sciences Seminar - Mapping phylogenetic trees to reveal distinct patterns of evolution
When:
—
Venue:
Birkbeck Main Building, Malet Street
No booking required
A phylogenetic tree or phylogeny is a diagrammatic representation of the evolutionary relationships between a set of organisms. Phylogenies are central to the study of evolution and are powerful tools for analysis in biology, epidemiology and beyond. For example, the phylogenetic tree of a virus can be used to infer who infected whom. However, phylogenetic inference (the process of determining the tree from the data) is complicated and tree uncertainty is a major obstacle in many analyses. One reason for this is that there are (2k-2)!! binary, rooted tree topologies for k organisms, making it infeasible to explore all possible topologies for k larger than about ten. Small changes in inference methods can lead to significant changes in the resulting phylogenies. Complicating factors such as non-tree-like evolution can mean that multiple phylogenies are equally well supported by a single data set.
We present a metric-based method to compare phylogenies. It enables the relative tree distances to be "mapped" into 2 or 3 dimensions so that the differences can be explored in a principled way. The method extracts and summarises distinct alternative evolutionary relationships embedded in data and resolves phylogenetic uncertainty. We demonstrate our approach on various organisms, revealing credible alternative evolutionary histories which were previously obscured within a Bayesian posterior set of trees.
Contact name:
Department of Economics, Mathematics and Statistics