Dr dos Reis is particularly interested in the development of statistical tools (Bayesian and likelihood) in evolutionary biology and their application in real data analysis. The two main themes of his current research are Bayesian estimation of the times of species divergences; and measuring the strength of natural selection in molecular sequences. Key achievements of his research include demonstrating that modern mammals diversified in the Paleogene, after the K-Pg extinction event that wiped out the dinosaurs; development of a method to measure the strength of selection coefficients from phylogenetic data; elucidating the timeline of evolution of the 1918 influenza pandemic virus; and development of a statistical measure to assess the level of translational optimisation of genes in a genome.