Fig 3. Phylogenetic distribution of conserved fern miRNAs.

The grid indicates the presence (green) or absence (white) of miRNA families in liverworts (M. polymorpha and/or P. endiviifolia), mosses (P. patens), lycopods (S. moellendorffii), ferns (P. minima and M. quadrifolia) as well as gymnosperms, basal angiosperms, monocots and dicots. For gymnosperms we took into account miRNAs of P. abies [6, 41], C. lanceolata [38] and T. mairei [39] and species reported in [23]; for angiosperms we included miRNAs of species reported in [23] and in miRBase release 21.0 [31]. Pairs of miRNAs that can be considered from the same family are indicated by coloured dots. Note that miRNAs are not necessarily present in all members of a group. Among liverworts, miR530/1030, miR529 and miR536 are only found in M. polymorpha, while miR156, miR395 and miR535 are only found in P. endiviifolia [36, 42, 43]. MiR403 and miR529 are absent from most non-dicot angiosperms [44] and eudicots [32, 33], respectively.