A general method for tree-comparison based on subtree similarity and its use in a taxonomic database

A number of metrics for comparing the branching structure of trees have been used as important tools in the quantitative analysis of evolutionary trees. Less attention has been paid to developing a general comparison methodology for different leaf-labeled N-trees such as classification trees and various types of dendrograms. In this paper a method for measuring overall similarity based on subtree similarity is proposed. Association coefficients can be used to measure the similarity between each pair of subtrees in two trees, and an algorithm called the 'webbing matrix method' is outlined in order to calculate the overall similarity in this method. In addition, the use of this method for tree searching and tree comparison in a taxonomic database is introduced. (C) 1997 Elsevier Science Ireland Ltd.