Reconstructing the Tree of Life: Building Large Trees from Short Sequences

Abstract: Markov models on trees (MMT) arise naturally in many areas of science, notably in Molecular Biology---as models of evolution---and in Statistical Physics--- as models of spin systems. In this talk, I will discuss various MMT inference problems motivated by applications in Statistical Phylogenetics, i.e., the reconstruction of evolutionary histories of organisms from their molecular sequences. I will begin with the "ancestral reconstruction" problem: how accurately can one guess the sequence of a deep ancestor, given the sequences of its current descendants? I will also discuss the related "phylogenetic reconstruction" problem: given the sequences of a set of species, how efficiently can one reconstruct their evolutionary history? Through deep connections between these two problems and insights from Statistical Physics, I will show that one can design novel, provably optimal reconstruction techniques.

Refreshments will be served at 2:45 p.m. (PIMS Lounge).