Estimates for the number of duplication events occurred at each major transition in the evolution of the eukaryotes. Species abbreviations are the same as in table 1. Horizontal bars indicate the average number of duplications per gene. Boxes on the right list some of the GO terms of the biological process category that are significantly over-represented compared to the rest of the genome in the set of gene families duplicated at a certain stage. A full list of significantly over represented terms is given as a table in the supplementary material .