Title
Gene Tree-Species Tree Relationships under the Coalescent Process
Speaker
Laura Salter, University of New Mexico
Abstract
Evolutionary relationships among a collection of organisms are commonly represented by phylogenetic trees, graphs composed of nodes and branches in which nodes represent hypothetical ancestors and branches represent ancestry-descent relationships. Phylogenies estimated from a single gene are called gene trees, and represent the history of only that gene. Various biological processes can produce gene histories that differ from the actual pattern of evolutionary divergence of the species, represented by the species tree. One important mechanism leading to incongruence between gene and species trees is the coalescent process. In this talk, the coalescent process will be described and an algorithm for computation of the probability distribution on gene tree topologies induced by the coalescent process will be given. Two applications of this gene tree distribution will then be discussed. The first is an examination of the performance of standard phylogenetic estimates under coalescence when data from multiple genes are concatenated. The second involves the derivation of marginal distributions of gene tree branch lengths. Examples of possible uses of these distributions will be given.
Meet the speaker in Room 212 Cockins Hall at 4:30 p.m. Refreshments will be served.
