Reconstruction of miRNA family evolution. These phylogenetic trees were generated to demonstrate the order of duplication events for three miRNA families. Circles indicate duplication events for which we have supporting evidence. Red circles indicate duplication events supported by conserved protein-coding genes flanking two miRNA genes. Green circles represent duplication events supported by conserved non-coding sequence flanking two miRNA genes. Blue circles indicate tandemly duplicated miRNAs. A combination of circles indicates that it is supported by multiple methods. The branch lengths are of uniform length and are not meant to indicate time since each duplication event. The connection between two green circles indicates that it is the same duplication event. Arrows establish which two miRNAs were found to be involved in a specific duplication event. (A) miR159 family; (B) miR166 family; (C) miR156 family.
