Clade size distribution under neutral evolutionary models.

Given a labeled tree topology t, consider a population P of k leaves chosen among those of t. The clade of P is the minimal subtree of t containing P and its size is given by the number of leaves in the clade. When t is selected under the Yule or uniform distribution among the labeled topologies of size n, we study the "clade size" random variable determining closed formulas for its probability mass function, its mean, and its variance.