If we took all of the single copy genes in all sequenced genomes, made phylogenetic trees from them individually, and then made the supertree of those trees, what would we get? Recently, David Pisani and colleagues did that experiment and their results are likely to spark much discussion. Their prokaryote tree looks very familiar, but the genome history of eukaryotes appears dominated by genes of cyanobacterial (plastid) and alpha-proteobacterial (mitochondrial) origin, while the host component branches within the archaebacteria.