Fig. 2

Distance between miRNA end and its nearest single-stranded nucleotide in the same miRNA strand. Considered are only those miRNA ends in which their terminal nucleotide is double-stranded. The frequencies of the 5′ miRNA ends are shown on panels (a) and (c). The frequencies of the 3′ miRNA ends are shown on panels (b) and (d). The data are presented for 5′ and 3′ miRNA sequences separately: for animal miRNAs excluding human and mouse ones (a and b) and for the human and mouse mirtrons and non-mirtrons (c and d). The positive values correspond to the distances to the nearest single-stranded nucleotide outside the miRNA. The negative values are the numbers of nucleotides that must be cut off from the miRNA to reach the nearest loop in the miRNA. The distance 0 is observed for those miRNA ends that are exactly at the boundary of the single-stranded region. The distance frequencies for all animal miRNAs (not shown) are the sum of results for all datasets and are only slightly different from the observations (a) and (b)