Title:
The geometry of model-based phylogenetics.

Speaker:
Erick Matsen, Miller fellow, Berkeley

Abstract:

Phylogenetics is the inference of evolutionary history of a set of
species using present-day sequence information. The most popular
phylogenetic methods today are model-based, such as likelihood and
Bayesian approaches. In this talk I will describe the geometric
perspective on model-based phylogenetics, and highlight two recent
successes of this viewpoint. First we describe in terms of convex
geometry why phylogenetic inference using concatenation of several
gene sequences can produce anomalous results. Second we present a
complete implicit characterization of the possible data sets
corresponding to phylogenetic trees under several popular models of
sequence evolution. This characterization shows that the relevant
model spaces live on the boundary of a non-convex higher dimensional
contractible space.