Taxonomic distribution of Mcm2-9 and a summarised phylogenetic tree of MCMs. This analysis shows that Mcm2-9 are present in the majority of the major eukaryotic 'supergroups' and that each MCM forms a moderate to strongly supported monophyletic group. Together these data demonstrate that Mcm2-9 were present in the last common eukaryotic ancestor. (A) Comparative genomic survey of MCM paralogues in 37 eukaryotic taxa. Mcm2-9 are shown on the x-axis and taxa are shown on the y-axis. Black circles indicate detections and open circles indicate no orthologues detected. Numbers within the black circles indicate the number of that specific MCM paralogue found in the taxa. Asterisks indicate species used for the "Noah's Ark" subset: for the results of the phylogenetic analysis see Additional file 5. (B) A summarised phylogenetic tree of MCMs based on Additional files 1, 2, 3, 4, emphasising the ML bootstrap support values for each MCM family, and relationships between each family which in most cases are weakly supported. The Archaea were used as an outgroup for reconstructing MCM phylogeny.