Adding vertical meaning to phylogenetic trees by artificial evolution

Abstract

Phylogenetic trees are the most commonly used method for representing the relationships among living organisms. Additive trees are often used to show evolutionary features, based on models of molecular evolution. In this case, information in the tree is contained only in the root-to-node direction or, in other words, in its topology. Indeed, in a typical left-to-right phylogram, the vertical order of taxa is meaningless, and the degree of similarity between taxa is reflected by the branch path between them. In an effort to make unresolved trees more informative, we applied a (1+1) Evolutionary Algorithm to find the best graphical tree representation that includes vertical information. The order of taxa linked to polytomic nodes is defined using data from distance matrices created from different features of taxa, such as genetic, temporal or geographical data. In this way, the vertical ordering of taxa on a phylogenetic tree can be used to represent non-genetic features of interest. © 2011 Springer-Verlag.