Ph.D. Dissertation Defense - Mukul Bansal

Date: 16 Apr, 2009
Time: 9:00 AM
Location: 223 Atanasoff Hall
Topic: Algorithms for Efficient Phylogenetic Tree Construction
Major Professor(s): David Fernandez-Baca


Abstract:

The fact that all life on Earth is genetically related is one of the most profound scientific observations of all time. Scientists have observed that these genealogical relationships among living things can (generally) be represented by a vast evolutionary tree, and constructing this tree of all life is a fundamental scientific problem facing human-kind today. Trees that depict evolutionary relationships between species, or other entities, are called phylogenetic trees or phylogenies.

The rapidly increasing amount of available genomic sequence data provides an abundance of potential information for phylogenetic analyses. Many models and methods have been developed to build evolutionary trees based on this information. Typically, to build a phylogenetic tree for a set of species, one constructs a phylogenetic tree from genes taken from those species. The implicit assumption is that the evolution of the chosen genes mimics the evolution of the species themselves. However, due to complex evolutionary processes such as gene duplication and loss, recombination, and horizontal gene transfer, as well as due to methodological issues, trees constructed on genes do not always accurately represent the evolutionary history of the corresponding species.

Here, we present two algorithms that greatly speed-up existing approaches for inferring a species phylogeny from several discordant gene trees. We also discuss a new distance measure for comparing phylogenetic trees.