Analyzing and Visualizing Sequence and Distance Data Using SplitsTree

In this paper, we describe and illustrate a tool for analyzing and visualizing sequence and distance data, called the splits-graph. The construction of this graph is based upon the split-decomposition technique which is a procedure to decompose a given metric de ned on a nite set in a canonical way into a sum of simpler metrics. In a way, this technique is comparable to Fourier analysis which also decomposes a given object under consideration (that is a periodic signal) into a sum of simpler such objects, in a canonical way. The splits-graph and the theory behind it have been developed mainly in Bielefeld over the last 5 years. The procedure for producing splits-graphs has been implemented in the SplitsTree program which we also describe and which is available from the authors.