occur; for example, migration between distant locales may never happen directly if air travel between the two places does not exist, so such migrations must pass through intermediate locales first. This means that there could be many parameters in the model which are zero or close to zero. To this end, Lemey and colleagues used a Bayesian procedure to not only estimate the parameters and ancestral states, but also to select which migration parameters are not zero; their work suggests that this procedure does lead to more efficient use of the data. They also explore the use of prior distributions that incorporate geographical structure or hypotheses about migration dynamics, finding that those they considered had little effect on the findings. Using this analysis, the team around Lemey found that the most likely hub of diffusion of A-H5N1 is Guangdong, with Hong Kong also receiving posterior support. Further, their results support the hypothesis of long-standing presence of African rabies in West Africa. Species ranges Inferring historical biogeographic patterns often requires reconstructing ancestral ranges of species on phylogenetic trees. For instance, a well-resolved phylogeny of plant species in the genus Cyrtandra was used together with information of their geographic ranges to compare four methods of ancestral range reconstruction. The team compared Fitch parsimony, (FP; parsimony) stochastic mapping (SM; maximum likelihood), dispersal-vicariance analysis (DIVA; parsimony), and dispersal-extinction-cladogenesis (DEC; maximum-likelihood). Results indicated that both parsimony methods performed poorly, which was likely due to the fact that parsimony methods do not consider branch lengths. Both maximum-likelihood methods performed better; however, DEC analyses that additionally allow incorporation of geological priors gave more realistic inferences about range evolution in Cyrtandra relative to other methods. Another maximum likelihood method recovers the phylogeographic history of a gene by reconstructing the ancestral locations of the sampled taxa. This method assumes a spatially explicit random walk model of migration to reconstruct ancestral locations given the geographic coordinates of the individuals represented by the tips of the phylogenetic tree. When applied to a phylogenetic tree of chorus frogs Pseudacris feriarum, this method recovered recent northward expansion, higher per-generation dispersal distance in the recently colonized region, a non-central ancestral location, and directional migration. The first consideration of the multiple genome rearrangement problem, long before its formalization in terms of permutations, was presented by Sturtevant and Dobzhansky in 1936. They examined genomes of several strains of fruit fly from different geographic locations, and observed