IMA Complex Systems Seminar
2:30 Wednesday, October 15, 2003
Department of Mathematics
Iowa State University
Ames, IA 50011
Abstract: Suppose that a tree T has the set S of leaves and S' is a subset of S. Then T|S' denotes the tree obtained from T with the set S' of leaves, showing only the relationships among S'. Suppose that for i = 1, ..., k, T_i is a tree with the set S_i of leaves. A "supertree" is a single tree T with the set S of leaves, where S is the union of the S_i, such that T|S_i = T_i for each i. A major problem in phylogeny is, given such a collection of trees T_i, to identify a supertree T if one exists. A method for solving this problem could be used to combine different phylogenetic trees from different researchers into a larger tree.
The most common method currently used to find supertrees is MRP (matrix representation with parsimony). It is computationally intensive, it often leads to a great many possible solution trees, and it is not founded on theory.
This talk proposes a supertree method in which additional input information is required. We require in addition that for each tree T_i there is given an additive distance function d_i on S_i which estimates the amount of evolution between any two taxa. We then try to create a supertree T with additive distance function d which equals d_i when restricted to S_i.
Some results of simulations will be presented.