Description:

Phylogenomics: Some Identifiability Results

Sebastien Roch, Professor in the Department of Mathematics, affiliated with the Department of Statistics and the Theory of Computing Group, University of Wisconsin-Madison

Abstract: The estimation of species phylogenies from genome-scale data is an important step in modern evolutionary studies. This estimation is complicated by the fact that genes evolve under biological processes that produce discordant trees. Such processes include horizontal gene transfer (HGT), gene duplication and loss (GDL), and incomplete lineage sorting (ILS), all of which can be modeled using random tree distributions. I will discuss recent results on the identifiability of these complex probabilistic models.

I will focus in particular on theoretical results for probabilistic models of HGT. Prior work has suggested the possibility of a “phase transition”, whereby reconstruction of the species tree may become significantly harder when the rate of transfer is high enough. I will report on recent work showing that, in fact, the species tree is identifiable for any rate of transfer, answering an open question in this area. Time permitting, I will also discuss the case of GDL.

No biology background will be assumed.