Mathematical Biology Seminar
Friday, March 4, 2016, 12:00pm, 119 Physics
Scott Schmidler (Duke statistics)
Stochastic Models of Protein Evolution

Abstract:

Stochastic evolutionary models of biological sequences are widely used for phylogenetic inference and ancestral reconstruction. However, at long divergence times sequences enter the "twilight zone" of homology detection and reconstruction becomes very difficult. We describe a stochastic evolutionary model for protein 3D structure using elements of shape theory. This model significantly resolves this uncertainty and stabilizes evolutionary inferences. We also provide theoretical bounds on inferring evolutionary divergence times via connections to the probabilistic "cutoff phenomenon", in which a Markov chain remains far equilibrium for an extended period followed by a rapid transition into equilibrium. We show that this cutoff explains several previously reported problems with common default priors for Bayesian phylogenetic analysis, and suggest a new class of priors to address these problems. [video]

---

Generated at 4:04am Wednesday, April 24, 2024 by Mcal.   Top * Reload * Login