Neighbor-joining phylogenetic tree of the Dicer protein family. Major organism groups (with colours) are mammals (red), birds (light red), cold-blooded vertebrates (deep blue), urochordates (light blue), deutrostome invertebrates (purple), protostome invertebrates (orange). plants (green), fungi (black), and protists (light purple). Stacks of three numbers show, in descending order, the percent occurrence of nodes in greater than 50% of 1000 bootstrap replicates of neighbor joining (plain text) and maximum parsimony (italicized text) or Bayesian posterior probability (only 0.90 or greater, in square parentheses). Asterisks ("*") indicate those nodes supported 60% or greater by the first two tree-building methods and 0.95 Bayesian posterior probability. Nodes with one or two values less than 50% have dashes ("-") while values less than 50% are unmarked. Scale bar represents 0.1 expected amino acid residue substitutions per site. The multiple sequence alignment file is given in Additional file 1.