Figure 3

Evolution of metazoan RNase III domains. a, Cladogram of isolated RNase III domains from metazoan Dicer and Drosha proteins. Mnemiopsis Dicer protein RNase III domains are labeled in red. Bootstrap support values above 45, based on 1000 bootstrap replicates, are displayed on branches with Bayesian probabilities as indicated. See Additional file 7: Table S1 for information on sequence identifiers. b, Scenario for Drosha evolution. Dicer proteins evolved from a duplicated RNase III domain early in eukaryotic evolution. Drosha proteins evolved from a duplicated Dicer protein early in metazoan evolution. White ‘a’ and ‘b’ labels represent RNase IIIa and RNase IIIb domains of Dicer and Drosha proteins, respectively. Green, yellow, pink and blue domains correspond with the clades shown in a.