Small RNA size distribution and base composition.

<p>The size distribution and base composition of small (17–29 nt) RNAs varied substantially amongst viruses. The barplots show the size distribution for those viruses with >100 small RNA reads (summed across all libraries; for a breakdown, see <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1002210#pbio.1002210.s013" target="_blank">S4 Fig</a>). Bars plotted above the <i>x</i>-axis represent reads mapping to the positive strand, and bars below represent reads mapping to the negative strand. All peak at 21 nt, except Kallithea Virus (a large DNA Nudivirus encoding a 22 nt miRNA) and Twyford Virus (Iflavirus), which peak at 22 nt. Note that DCV, Kilifi, Thika, and Nora Virus show a wide shoulder, up to 28 nt for positive-strand reads, which may indicate a difference in small RNA processing or retention. Bars are coloured according to the proportion of reads with each 5'-base (A-green, C-blue, G-yellow, U-red), and all except Twyford Virus show the expected pattern, including a slight bias against G at the 5' position. Counts used to plot this figure are provided in <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1002210#pbio.1002210.s001" target="_blank">S1 Data</a>.