Figure 3. Examples of some common moves used in Bayesian phylogenetic inference.

Scaling and sliding moves operate on a numerical parameter ( X), such as the molecular clock rate, the speciation rate or the age of a fossil, and generally use a uniform distribution ( U). Scaling moves use a scaling factor s chosen uniformly at random in the scaling range defined by the move parameter a. Sliding moves pick a new value uniformly at random in a window given by the window size parameter d. Subtree exchange (STX) and subtree pruning and regrafting (SPR) moves operate on the tree topology by moving subclades (represented as coloured triangles). A more detailed description of these moves can be found in Drummond et al. (2002).