A Simple Stochastic Model of Speciation
by
Andy McKenzie
Biomathematics Research Centre, University of Canterbury, Christchurch
Coauthors: Mike Steel (University of Canterbury)

We investigate some properties of evolutionary trees generated under a simple stochastic model of speciation. This model has been used to supply prior probabilities in Bayesian approaches to phylogenetic analysis, and also to test hypotheses concerning the speciation process.

Firstly, we find the probability distribution for the distance of a randomly chosen species from the root of the tree. Next we find a formula for the mean distance between two randomly chosen species. Finally, we show that the approximate position of the root can be estimated from the associated unrooted tree, even for trees with a large number of species.

Date received: September 27, 2000