Scientists from the US and from the Evolutionary biology Centre at Uppsala University have now developed computer-based methods for Bayesian inference of problems in evolutionary biology. The basic idea is to allow the computer to walk around, according to certain rules, in a landscape defined by the relative probability of different evolutionary scenarios. By allowing the computer to jump between a normal landscape and heated landscapes, in which hilltops and valleys are less clearly separated, the computer can quickly find the hilltops, corresponding to the most likely evolutionary scenarios. In a paper published in Science, December 14, the Swedish-American group shows how problems that have previously been too difficult for supercomputers can now be analysed using an ordinary desktop computer. The new methods can be applied to a wide range of problems, including reconstruction of relationships among species, clarification of viral transmission pathways, and studies of the mechanisms of molecular evolution.